fix: Update ElCLib 2D/3D point conversion API in ViewportWidget

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

CMakeLists.txt

@@ -28,20 +28,33 @@ endif()
 message(STATUS "OpenCASCADE_INCLUDE_DIRS: ${OpenCASCADE_INCLUDE_DIRS}")
 message(STATUS "OpenCASCADE_LIBRARIES: ${OpenCASCADE_LIBRARIES}")
 
+# Automatically find resource files and generate resources.qrc
+set(GENERATED_QRC_FILE "${CMAKE_CURRENT_BINARY_DIR}/resources.qrc")
+set(QRC_CONTENT "")
+
+file(GLOB ICON_FILES "icons/*.svg")
+string(APPEND QRC_CONTENT "    <qresource prefix=\"/icons\">\n")
+foreach(ICON_FILE IN LISTS ICON_FILES)
+    get_filename_component(ICON_ALIAS ${ICON_FILE} NAME)
+    string(APPEND QRC_CONTENT "        <file alias=\"${ICON_ALIAS}\">${ICON_FILE}</file>\n")
+endforeach()
+string(APPEND QRC_CONTENT "    </qresource>\n")
+
+file(GLOB SHADER_FILES "src/shaders/*")
+string(APPEND QRC_CONTENT "    <qresource prefix=\"/shaders\">\n")
+foreach(SHADER_FILE IN LISTS SHADER_FILES)
+    get_filename_component(SHADER_ALIAS ${SHADER_FILE} NAME)
+    string(APPEND QRC_CONTENT "        <file alias=\"${SHADER_ALIAS}\">${SHADER_FILE}</file>\n")
+endforeach()
+string(APPEND QRC_CONTENT "    </qresource>\n")
+
+file(WRITE ${GENERATED_QRC_FILE} "<RCC>\n${QRC_CONTENT}</RCC>\n")
+
+file(GLOB SOURCES "src/*.cpp")
+
 add_executable(OpenCAD
-    src/main.cpp
+    ${SOURCES}
-    src/MainWindow.cpp
+    ${GENERATED_QRC_FILE}
-    src/ViewportWidget.cpp
-    src/ViewCube.cpp
-    src/SketchGrid.cpp
-    src/Document.cpp
-    src/Feature.cpp
-    src/SketchFeature.cpp
-    src/SketchLine.cpp
-    src/FeatureBrowser.cpp
-	src/ApplicationController.cpp
-	src/Camera.cpp
-    resources.qrc
 )
 
 target_include_directories(OpenCAD SYSTEM PRIVATE ${OpenCASCADE_INCLUDE_DIRS})

LICENSE.txt

@@ -0,0 +1,674 @@
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+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    {{ project }}  Copyright (C) {{ year }}  {{ organization }}
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

README.md

@@ -0,0 +1,28 @@
+# Unnamed CAD Software
+
+## Development
+
+### Building
+
+On Debian 12:
+
+```bash
+$ sudo apt install cmake qt6-base-dev qt6-svg-dev libtbb-dev libfontconfig1-dev
+$ sudo apt install libocct-foundation-dev libocct-modeling-data-dev libocct-modeling-algorithms-dev libocct-visualization-dev
+
+$ mkdir build
+$ cd build/
+$ cmake ..
+$ make
+
+$ ./OpenCAD
+```
+
+
+
+## License
+
+This program is free and open-source software licensed under the GNU GPLv3 (or later). Please see the `LICENSE.txt` file for details.
+
+That means you have the right to study, change, and distribute the software and source code to anyone and for any purpose as long as you grant the same rights when distributing it.
+

icons/home.svg

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   viewBox="0 0 24 24"
+   fill="currentColor"
+   class="size-6"
+   version="1.1"
+   id="svg2"
+   sodipodi:docname="home.svg"
+   inkscape:version="1.4 (e7c3feb100, 2024-10-09)"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs2" />
+  <sodipodi:namedview
+     id="namedview2"
+     pagecolor="#ffffff"
+     bordercolor="#000000"
+     borderopacity="0.25"
+     inkscape:showpageshadow="2"
+     inkscape:pageopacity="0.0"
+     inkscape:pagecheckerboard="0"
+     inkscape:deskcolor="#d1d1d1"
+     inkscape:zoom="14.574147"
+     inkscape:cx="6.9643869"
+     inkscape:cy="8.6797532"
+     inkscape:window-width="1440"
+     inkscape:window-height="831"
+     inkscape:window-x="0"
+     inkscape:window-y="0"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg2" />
+  <path
+     d="M11.47 3.841a.75.75 0 0 1 1.06 0l8.69 8.69a.75.75 0 1 0 1.06-1.061l-8.689-8.69a2.25 2.25 0 0 0-3.182 0l-8.69 8.69a.75.75 0 1 0 1.061 1.06l8.69-8.689Z"
+     id="path1"
+     style="fill:#ffffff" />
+  <path
+     d="m12 5.432 8.159 8.159c.03.03.06.058.091.086v6.198c0 1.035-.84 1.875-1.875 1.875H15a.75.75 0 0 1-.75-.75v-4.5a.75.75 0 0 0-.75-.75h-3a.75.75 0 0 0-.75.75V21a.75.75 0 0 1-.75.75H5.625a1.875 1.875 0 0 1-1.875-1.875v-6.198a2.29 2.29 0 0 0 .091-.086L12 5.432Z"
+     id="path2"
+     style="fill:#ffffff" />
+</svg>

resources.qrc

@@ -1,17 +0,0 @@
-<RCC>
-    <qresource prefix="/">
-        <file>icons/create-sketch.svg</file>
-        <file>icons/extrude.svg</file>
-		<file>icons/line.svg</file>
-		<file>icons/rectangle.svg</file>
-		<file>icons/circle.svg</file>
-		<file>icons/save-sketch.svg</file>
-		<file>icons/cursor.svg</file>
-    </qresource>
-    <qresource prefix="/shaders">
-        <file alias="simple.vert">src/shaders/simple.vert</file>
-        <file alias="simple.frag">src/shaders/simple.frag</file>
-        <file alias="texture.vert">src/shaders/texture.vert</file>
-        <file alias="texture.frag">src/shaders/texture.frag</file>
-    </qresource>
-</RCC>

src/ApplicationController.cpp

@@ -1,9 +1,28 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "ApplicationController.h"
 #include "Document.h"
 #include "SketchFeature.h"
 #include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchCircle.h"
 #include "MainWindow.h"
 
+#include <BRepBuilderAPI_MakeEdge.hxx>
+#include <BRepBuilderAPI_MakeWire.hxx>
+#include <GC_MakeSegment.hxx>
+#include <ElCLib.hxx>
+#include <gp_Ax2.hxx>
+#include <gp_Circ.hxx>
+#include <gp_Dir.hxx>
+#include <gp_Vec.hxx>
+#include <gp_Pnt2d.hxx>
+
 #include <QInputDialog>
 #include <QFileDialog>
 #include <QMessageBox>
@@ -108,26 +127,12 @@ void ApplicationController::beginSketchCreation()
     emit planeSelectionModeStarted();
 }
 
-void ApplicationController::onPlaneSelected(ViewportWidget::SketchPlane plane)
+void ApplicationController::onPlaneSelected(const gp_Ax2& plane)
 {
     auto feature = new SketchFeature("Sketch");
     m_activeSketch = feature;
 
-    switch (plane) {
+    feature->setPlane(plane);
-        case ViewportWidget::SketchPlane::XY:
-            feature->setPlane(SketchFeature::SketchPlane::XY);
-            break;
-        case ViewportWidget::SketchPlane::XZ:
-            feature->setPlane(SketchFeature::SketchPlane::XZ);
-            break;
-        case ViewportWidget::SketchPlane::YZ:
-            feature->setPlane(SketchFeature::SketchPlane::YZ);
-            break;
-        case ViewportWidget::SketchPlane::NONE:
-            delete feature;
-            m_activeSketch = nullptr;
-            return;
-    }
 
     m_document->addFeature(feature);
     emit sketchModeStarted(plane);
@@ -137,6 +142,52 @@ void ApplicationController::addLine(const gp_Pnt& start, const gp_Pnt& end)
 {
     if (m_activeSketch) {
         m_activeSketch->addObject(new SketchLine(start, end));
+
+        Handle(Geom_TrimmedCurve) segment = GC_MakeSegment(start, end);
+        TopoDS_Edge edge = BRepBuilderAPI_MakeEdge(segment);
+        m_activeSketch->addShape(edge);
+    }
+}
+
+void ApplicationController::addRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2)
+{
+    if (m_activeSketch) {
+        m_activeSketch->addObject(new SketchRectangle(corner1, corner2));
+
+        const auto& plane = m_activeSketch->plane();
+
+        gp_Pnt2d p1_2d(gp_Vec(plane.Location(), corner1).Dot(plane.XDirection()), gp_Vec(plane.Location(), corner1).Dot(plane.YDirection()));
+        gp_Pnt2d p3_2d(gp_Vec(plane.Location(), corner2).Dot(plane.XDirection()), gp_Vec(plane.Location(), corner2).Dot(plane.YDirection()));
+
+        gp_Pnt2d p2_2d(p3_2d.X(), p1_2d.Y());
+        gp_Pnt2d p4_2d(p1_2d.X(), p3_2d.Y());
+
+        gp_Pnt p2_3d = ElCLib::To3d(plane, p2_2d);
+        gp_Pnt p4_3d = ElCLib::To3d(plane, p4_2d);
+
+        TopoDS_Edge e1 = BRepBuilderAPI_MakeEdge(corner1, p2_3d);
+        TopoDS_Edge e2 = BRepBuilderAPI_MakeEdge(p2_3d, corner2);
+        TopoDS_Edge e3 = BRepBuilderAPI_MakeEdge(corner2, p4_3d);
+        TopoDS_Edge e4 = BRepBuilderAPI_MakeEdge(p4_3d, corner1);
+
+        BRepBuilderAPI_MakeWire wireMaker(e1, e2, e3, e4);
+        if (wireMaker.IsDone()) {
+            m_activeSketch->addShape(wireMaker.Shape());
+        }
+    }
+}
+
+void ApplicationController::addCircle(const gp_Pnt& center, double radius)
+{
+    if (m_activeSketch) {
+        m_activeSketch->addObject(new SketchCircle(center, radius));
+
+        const auto& sketchPlane = m_activeSketch->plane();
+        gp_Ax2 axis(center, sketchPlane.Direction());
+
+        gp_Circ circle(axis, radius);
+        TopoDS_Edge edge = BRepBuilderAPI_MakeEdge(circle);
+        m_activeSketch->addShape(edge);
     }
 }
 

src/ApplicationController.h

@@ -1,9 +1,16 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef APPLICATIONCONTROLLER_H
 #define APPLICATIONCONTROLLER_H
 
 #include <QObject>
-#include "ViewportWidget.h" // For SketchPlane enum
 #include <gp_Pnt.hxx>
+#include <gp_Ax2.hxx>
 
 class Document;
 class MainWindow;
@@ -32,18 +39,20 @@ public:
 public slots:
     void setActiveTool(ToolType tool);
     void addLine(const gp_Pnt& start, const gp_Pnt& end);
+    void addRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2);
+    void addCircle(const gp_Pnt& center, double radius);
     void newDocument();
     bool openDocument();
     bool saveDocument();
     bool saveDocumentAs();
 
     void beginSketchCreation();
-    void onPlaneSelected(ViewportWidget::SketchPlane plane);
+    void onPlaneSelected(const gp_Ax2& plane);
     void endSketch();
 
 signals:
     void planeSelectionModeStarted();
-    void sketchModeStarted(ViewportWidget::SketchPlane plane);
+    void sketchModeStarted(const gp_Ax2& plane);
     void sketchModeEnded();
     void currentFileChanged(const QString& path);
     void activeToolChanged(ToolType tool);

src/Camera.cpp

@@ -1,9 +1,22 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "Camera.h"
+#include <gp_Ax2.hxx>
+#include <gp_Dir.hxx>
 #include <QApplication>
 #include <QWheelEvent>
+#include <QPropertyAnimation>
+#include <QParallelAnimationGroup>
+#include <QtMath>
 
 Camera::Camera(QObject *parent) : QObject(parent)
 {
+    m_lastPos = QPoint();
     // Set initial view to an isometric angle on the XY plane
     m_xRot = 30 * 16;
     m_yRot = -45 * 16;
@@ -12,29 +25,72 @@ Camera::Camera(QObject *parent) : QObject(parent)
     m_panY = 0.0f;
 }
 
-void Camera::processMouseMovement(QMouseEvent* event, const QPoint& lastPos)
+void Camera::mousePressEvent(QMouseEvent* event)
 {
-    int dx = event->pos().x() - lastPos.x();
+    m_lastPos = event->pos();
-    int dy = event->pos().y() - lastPos.y();
+}
 
-    if (event->buttons() & Qt::MiddleButton) {
+void Camera::mouseMoveEvent(QMouseEvent* event, int viewportHeight)
+{
+    int dx = event->pos().x() - m_lastPos.x();
+    int dy = event->pos().y() - m_lastPos.y();
+
+    if ((event->buttons() & Qt::MiddleButton) || (event->buttons() == (Qt::LeftButton | Qt::RightButton))) {
         if (QApplication::keyboardModifiers() & Qt::ShiftModifier) {
             // Pan
-            setPanX(m_panX + dx / 100.0f);
+            if (viewportHeight == 0) viewportHeight = 1;
-            setPanY(m_panY - dy / 100.0f);
+
+            // This logic is based on a 45-degree field of view.
+            float fov = 45.0f;
+            float dist = -m_zoom;
+
+            float world_height = 2.0f * dist * tan(qDegreesToRadians(fov / 2.0f));
+            float pixels_to_world = world_height / viewportHeight;
+
+            setPanX(m_panX + dx * pixels_to_world);
+            setPanY(m_panY - dy * pixels_to_world);
         } else {
             // Rotate
             setXRotation(m_xRot + 8 * dy);
             setYRotation(m_yRot + 8 * dx);
         }
     }
+    m_lastPos = event->pos();
 }
 
-void Camera::processWheel(QWheelEvent* event)
+void Camera::wheelEvent(QWheelEvent* event, const QVector3D& worldPos)
 {
     QPoint numDegrees = event->angleDelta() / 8;
     if (!numDegrees.isNull()) {
-        setZoom(m_zoom + numDegrees.y() / 5.0f);
+        // Make zoom speed proportional to distance, with a minimum speed and a cap.
+        // The factors are chosen to match the original zoom speed at the default zoom level.
+        float dist = -m_zoom;
+        dist = qMin(dist, 200.0f); // Cap distance to avoid crazy fast zoom out.
+        float zoomFactor = dist * 0.009f + 0.02f;
+        float zoomAmount = numDegrees.y() * zoomFactor;
+
+        float oldZoom = m_zoom;
+        float newZoom = oldZoom + zoomAmount;
+
+        QMatrix4x4 rotation;
+        rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+        rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+        rotation.rotate(-90.0f, 1, 0, 0);
+        QVector3D p_camera = rotation.map(worldPos);
+
+        if (std::abs(p_camera.z() + oldZoom) < 1e-6) {
+            setZoom(newZoom);
+            return;
+        }
+
+        float ratio = (p_camera.z() + newZoom) / (p_camera.z() + oldZoom);
+
+        float newPanX = (p_camera.x() + m_panX) * ratio - p_camera.x();
+        float newPanY = (p_camera.y() + m_panY) * ratio - p_camera.y();
+
+        setZoom(newZoom);
+        setPanX(newPanX);
+        setPanY(newPanY);
     }
 }
 
@@ -42,8 +98,21 @@ QMatrix4x4 Camera::modelViewMatrix() const
 {
     QMatrix4x4 model;
     model.translate(m_panX, m_panY, m_zoom);
+
+    QMatrix4x4 zup_rotation;
+    zup_rotation.rotate(-90.0f, 1, 0, 0);
+    QVector3D pivot_yup = zup_rotation.map(m_rotationPivot);
+
+    if (m_isRotating) {
+        model.translate(pivot_yup);
+    }
     model.rotate(m_xRot / 16.0f, 1, 0, 0);
     model.rotate(m_yRot / 16.0f, 0, 1, 0);
+    if (m_isRotating) {
+        model.translate(-pivot_yup);
+    }
+
+    model.rotate(-90.0f, 1, 0, 0); // For Z-up system
     return model;
 }
 
@@ -68,6 +137,14 @@ void Camera::setYRotation(float angle)
 float Camera::zoom() const { return m_zoom; }
 void Camera::setZoom(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panX * m_panX - m_panY * m_panY;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, 0.0f); // Zoom is negative or zero
+
     if (value != m_zoom) {
         m_zoom = value;
         emit cameraChanged();
@@ -77,6 +154,14 @@ void Camera::setZoom(float value)
 float Camera::panX() const { return m_panX; }
 void Camera::setPanX(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panY * m_panY - m_zoom * m_zoom;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, max_val);
+
     if (value != m_panX) {
         m_panX = value;
         emit cameraChanged();
@@ -86,6 +171,14 @@ void Camera::setPanX(float value)
 float Camera::panY() const { return m_panY; }
 void Camera::setPanY(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panX * m_panX - m_zoom * m_zoom;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, max_val);
+
     if (value != m_panY) {
         m_panY = value;
         emit cameraChanged();
@@ -109,3 +202,275 @@ void Camera::restoreState()
     setPanY(m_savedPanY);
     setZoom(m_savedZoom);
 }
+
+void Camera::animateToPlaneView(const gp_Ax2& plane)
+{
+    const auto& normal = plane.Direction();
+    QVector3D n(normal.X(), normal.Y(), normal.Z());
+    QVector3D d;
+
+    // This logic preserves the quirky view directions of the original implementation.
+    // For XZ-like planes (normal is mostly along Y), the view is aligned WITH the plane normal.
+    // For other planes, it's aligned AGAINST the normal.
+    if (qAbs(n.y()) > 0.99) {
+        d = n;
+    } else {
+        d = -n;
+    }
+
+    float targetXRot = qRadiansToDegrees(asin(-d.z())) * 16.0f;
+    float targetYRot;
+
+    if (qAbs(d.z()) > 0.9999) { // Top/bottom-like view, Y rotation is arbitrary
+        targetYRot = 0; // Set to 0 for stability
+    } else {
+        targetYRot = qRadiansToDegrees(atan2(d.x(), d.y())) * 16.0f;
+    }
+
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(0.0f);
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(0.0f);
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(-20.0f);
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+void Camera::animateToHomeView()
+{
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float targetXRot = 30 * 16;
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float targetYRot = -45 * 16;
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(0.0f);
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(0.0f);
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(-20.0f);
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+void Camera::startRotation(const QVector3D& pivot)
+{
+    m_rotationPivot = pivot;
+    if (m_rotationPivot.length() > 1000.0f) {
+        m_rotationPivot = m_rotationPivot.normalized() * 1000.0f;
+    }
+    m_stableZoom = m_zoom;
+
+    QMatrix4x4 zup_rotation;
+    zup_rotation.rotate(-90.0f, 1, 0, 0);
+    QVector3D pivot_yup = zup_rotation.map(m_rotationPivot);
+
+    QMatrix4x4 rotation;
+    rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+    rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+
+    QVector3D p_rotated = rotation.map(pivot_yup);
+    QVector3D p_diff = p_rotated - pivot_yup;
+
+    setPanX(m_panX + p_diff.x());
+    setPanY(m_panY + p_diff.y());
+    setZoom(m_zoom + p_diff.z());
+
+    m_isRotating = true;
+}
+
+void Camera::stopRotation()
+{
+    if (!m_isRotating) {
+        return;
+    }
+
+    QMatrix4x4 zup_rotation;
+    zup_rotation.rotate(-90.0f, 1, 0, 0);
+    QVector3D pivot_yup = zup_rotation.map(m_rotationPivot);
+
+    QMatrix4x4 rotation;
+    rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+    rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+
+    QVector3D p_rotated = rotation.map(pivot_yup);
+    QVector3D p_diff = p_rotated - pivot_yup;
+
+    setPanX(m_panX - p_diff.x());
+    setPanY(m_panY - p_diff.y());
+    setZoom(m_zoom - p_diff.z());
+
+    m_isRotating = false;
+}
+
+void Camera::animateRestoreState()
+{
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float targetXRot = savedXRot();
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float targetYRot = savedYRot();
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(savedPanX());
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(savedPanY());
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(savedZoom());
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    connect(animGroup, &QParallelAnimationGroup::finished, this, &Camera::restoreStateAnimationFinished);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+float Camera::uiCameraDistance() const
+{
+    if (m_isRotating) {
+        return m_stableZoom;
+    }
+    return m_zoom;
+}

src/Camera.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef CAMERA_H
 #define CAMERA_H
 
@@ -7,6 +14,8 @@
 #include <QMouseEvent>
 #include <QWheelEvent>
 
+#include <gp_Ax2.hxx>
+
 class Camera : public QObject
 {
     Q_OBJECT
@@ -19,8 +28,9 @@ class Camera : public QObject
 public:
     explicit Camera(QObject *parent = nullptr);
 
-    void processMouseMovement(QMouseEvent* event, const QPoint& lastPos);
+    void mousePressEvent(QMouseEvent* event);
-    void processWheel(QWheelEvent* event);
+    void mouseMoveEvent(QMouseEvent* event, int viewportHeight);
+    void wheelEvent(QWheelEvent* event, const QVector3D& worldPos);
 
     QMatrix4x4 modelViewMatrix() const;
 
@@ -38,6 +48,16 @@ public:
     void saveState();
     void restoreState();
 
+    void animateToPlaneView(const gp_Ax2& plane);
+    void animateRestoreState();
+    void animateToHomeView();
+
+    void startRotation(const QVector3D& pivot);
+    void stopRotation();
+    bool isRotating() const { return m_isRotating; }
+    const QVector3D& rotationPivot() const { return m_rotationPivot; }
+    float uiCameraDistance() const;
+
     float savedXRot() const { return m_savedXRot; }
     float savedYRot() const { return m_savedYRot; }
     float savedZoom() const { return m_savedZoom; }
@@ -46,14 +66,20 @@ public:
 
 signals:
     void cameraChanged();
+    void restoreStateAnimationFinished();
 
 private:
+    QPoint m_lastPos;
     float m_xRot;
     float m_yRot;
     float m_zoom;
     float m_panX;
     float m_panY;
 
+    QVector3D m_rotationPivot;
+    bool m_isRotating = false;
+    float m_stableZoom = 0;
+
     float m_savedXRot = 0;
     float m_savedYRot = 0;
     float m_savedZoom = -5.0f;

src/CircleTool.cpp

@@ -0,0 +1,268 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "CircleTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QVector>
+#include <QOpenGLShaderProgram>
+#include <cmath>
+#include <QtMath>
+#include <optional>
+#include <gp_Ax2.hxx>
+#include <gp_Pnt2d.hxx>
+#include <ElCLib.hxx>
+
+CircleTool::CircleTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void CircleTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes.clear();
+    m_dimensionModes << "diameter";
+    m_dimensionPropertyNames.clear();
+    m_dimensionPropertyNames["diameter"] = "diameterInput";
+
+    m_viewport->setProperty("diameterInput", "");
+    m_viewport->setProperty("dimensionEditMode", "diameter");
+}
+
+void CircleTool::mousePressEvent(QMouseEvent *event)
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    gp_Pnt p;
+    if (!m_isDefining) {
+        if (m_viewport->isSnappingOrigin()) {
+            p = plane.Location();
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPos = m_viewport->unproject(event->pos(), plane);
+            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        }
+        m_centerPoint = p;
+        m_isDefining = true;
+
+        m_dimensionModes.clear();
+        m_dimensionModes << "diameter";
+        m_dimensionPropertyNames.clear();
+        m_dimensionPropertyNames["diameter"] = "diameterInput";
+
+        m_viewport->setProperty("diameterInput", "");
+        m_viewport->setProperty("dimensionEditMode", "diameter");
+    } else {
+        QVector3D worldPos;
+        QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+        QString diameterInput = m_viewport->property("diameterInput").toString();
+        bool diameterFromInput = false;
+        double inputDiameter = 0;
+
+        if (!diameterInput.isEmpty()) {
+            bool ok;
+            inputDiameter = diameterInput.toDouble(&ok);
+            if (ok) diameterFromInput = true;
+        }
+
+        if (diameterFromInput) {
+            QVector3D mousePos = m_viewport->unproject(event->pos(), plane);
+            QVector3D mouseDir = mousePos - centerPos;
+            if (mouseDir.lengthSquared() < 1e-9) {
+                const auto& xDir = plane.XDirection();
+                mouseDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+            double radius = inputDiameter / 2.0;
+            worldPos = centerPos + mouseDir.normalized() * radius;
+        } else {
+            if (m_viewport->isSnappingOrigin()) {
+                const auto& origin = plane.Location();
+                worldPos.setX(origin.X()); worldPos.setY(origin.Y()); worldPos.setZ(origin.Z());
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos = QVector3D(m_viewport->snapVertex().X(), m_viewport->snapVertex().Y(), m_viewport->snapVertex().Z());
+            } else {
+                worldPos = m_viewport->unproject(event->pos(), plane);
+            }
+        }
+        p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        emit m_viewport->circleAdded(m_centerPoint, m_centerPoint.Distance(p));
+        deactivate();
+    }
+}
+
+void CircleTool::mouseMoveEvent(QMouseEvent *event)
+{
+    // To be implemented
+}
+
+void CircleTool::finalizeCreation()
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector3D worldPos;
+    QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+    QString diameterInput = m_viewport->property("diameterInput").toString();
+    bool diameterFromInput = false;
+    double inputDiameter = 0;
+
+    if (!diameterInput.isEmpty()) {
+        bool ok;
+        inputDiameter = diameterInput.toDouble(&ok);
+        if (ok) diameterFromInput = true;
+    }
+
+    if (diameterFromInput) {
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+        QVector3D mouseDir = mousePos - centerPos;
+        if (mouseDir.lengthSquared() < 1e-9) {
+            const auto& xDir = plane.XDirection();
+            mouseDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+        }
+        double radius = inputDiameter / 2.0;
+        worldPos = centerPos + mouseDir.normalized() * radius;
+    } else {
+        worldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+
+    emit m_viewport->circleAdded(m_centerPoint, m_centerPoint.Distance(p));
+    deactivate();
+}
+
+void CircleTool::paintGL()
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!m_isDefining || !currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector<GLfloat> vertices;
+    QVector3D worldPos;
+    QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+    QString diameterInput = m_viewport->property("diameterInput").toString();
+    bool diameterFromInput = false;
+    double inputDiameter = 0;
+
+    if (!diameterInput.isEmpty()) {
+        bool ok;
+        inputDiameter = diameterInput.toDouble(&ok);
+        if (ok) diameterFromInput = true;
+    }
+
+    QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+
+    double radius;
+    if (diameterFromInput) {
+        radius = inputDiameter / 2.0;
+    } else {
+        worldPos = mousePos;
+        if (m_viewport->isSnappingOrigin()) {
+            const auto& origin = plane.Location();
+            worldPos.setX(origin.X()); worldPos.setY(origin.Y()); worldPos.setZ(origin.Z());
+        } else if (m_viewport->isSnappingVertex()) {
+            worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+        }
+        radius = (worldPos - centerPos).length();
+    }
+
+    const int segments = 64;
+    const auto& xDir = plane.XDirection();
+    const auto& yDir = plane.YDirection();
+    QVector3D u_axis(xDir.X(), xDir.Y(), xDir.Z());
+    QVector3D v_axis(yDir.X(), yDir.Y(), yDir.Z());
+
+    for (int i = 0; i < segments; ++i) {
+        double angle1 = i * 2.0 * M_PI / segments;
+        double angle2 = (i + 1) * 2.0 * M_PI / segments;
+
+        QVector3D p1 = centerPos + radius * (qCos(angle1) * u_axis + qSin(angle1) * v_axis);
+        QVector3D p2 = centerPos + radius * (qCos(angle2) * u_axis + qSin(angle2) * v_axis);
+
+        vertices << p1.x() << p1.y() << p1.z();
+        vertices << p2.x() << p2.y() << p2.z();
+    }
+
+    m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+    m_viewport->vbo().bind();
+    m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+    glDrawArrays(GL_LINES, 0, segments * 2);
+}
+
+void CircleTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!m_isDefining || !currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector3D worldPos;
+    QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+    QString diameterInput = m_viewport->property("diameterInput").toString();
+    bool diameterFromInput = false;
+    double inputDiameter = 0;
+
+    if (!diameterInput.isEmpty()) {
+        bool ok;
+        inputDiameter = diameterInput.toDouble(&ok);
+        if (ok) diameterFromInput = true;
+    }
+
+    QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    QVector3D edgePos;
+    double diameter;
+
+    if (diameterFromInput) {
+        diameter = inputDiameter;
+        QVector3D mouseDir = mousePos - centerPos;
+        if (mouseDir.lengthSquared() < 1e-9) {
+            const auto& xDir = plane.XDirection();
+            mouseDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+        }
+        edgePos = centerPos + mouseDir.normalized() * (diameter / 2.0);
+    } else {
+        edgePos = mousePos;
+        if (m_viewport->isSnappingOrigin()) {
+            const auto& origin = plane.Location();
+            edgePos.setX(origin.X()); edgePos.setY(origin.Y()); edgePos.setZ(origin.Z());
+        } else if (m_viewport->isSnappingVertex()) {
+            edgePos.setX(m_viewport->snapVertex().X()); edgePos.setY(m_viewport->snapVertex().Y()); edgePos.setZ(m_viewport->snapVertex().Z());
+        }
+        diameter = (edgePos - centerPos).length() * 2.0;
+    }
+
+    painter.setRenderHint(QPainter::Antialiasing);
+    QFontMetrics fm(painter.font());
+
+    // Diameter dimension
+    QVector3D diameterTextPos3D = (centerPos + edgePos) / 2.0f;
+    QVector3D screenPosD = m_viewport->project(diameterTextPos3D, modelView, projection, m_viewport->rect());
+    if (screenPosD.z() < 1.0f) {
+        QString diameterText = diameterFromInput ? diameterInput : QString::number(diameter, 'f', 2);
+        QRect textRect = fm.boundingRect(diameterText + "__");
+        textRect.moveCenter(screenPosD.toPoint());
+        if (m_viewport->property("dimensionEditMode").toString() == "diameter") {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+        } else {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+        }
+        painter.setPen(Qt::white);
+        painter.drawText(textRect, Qt::AlignCenter, diameterText);
+    }
+}

src/CircleTool.h

@@ -0,0 +1,35 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef CIRCLETOOL_H
+#define CIRCLETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class CircleTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit CircleTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_centerPoint;
+};
+
+#endif // CIRCLETOOL_H

src/DebugWindow.cpp

@@ -0,0 +1,55 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "DebugWindow.h"
+#include "Camera.h"
+
+#include <QVBoxLayout>
+#include <QTextEdit>
+#include <QString>
+
+DebugWindow::DebugWindow(QWidget *parent)
+    : QDialog(parent)
+{
+    setWindowTitle("Debug Info");
+    resize(600, 400);
+
+    QVBoxLayout* layout = new QVBoxLayout(this);
+    m_textEdit = new QTextEdit();
+    m_textEdit->setReadOnly(true);
+    m_textEdit->setText("Debug window is active.");
+    layout->addWidget(m_textEdit);
+    setLayout(layout);
+}
+
+DebugWindow::~DebugWindow()
+{
+}
+
+void DebugWindow::updateCameraInfo(const Camera* camera)
+{
+    if (!camera) {
+        m_textEdit->setText("Camera not available.");
+        return;
+    }
+
+    QString info;
+    info += "Camera Info:\n";
+    info += "----------------\n";
+    info += QString("Rotation (X, Y): (%1, %2)\n").arg(camera->xRotation()).arg(camera->yRotation());
+    info += QString("Zoom: %1\n").arg(camera->zoom());
+    info += QString("Pan (X, Y): (%1, %2)\n").arg(camera->panX()).arg(camera->panY());
+    info += QString("UI Camera Distance: %1\n").arg(camera->uiCameraDistance());
+    info += "\n";
+    info += "Saved State:\n";
+    info += "----------------\n";
+    info += QString("Rotation (X, Y): (%1, %2)\n").arg(camera->savedXRot()).arg(camera->savedYRot());
+    info += QString("Zoom: %1\n").arg(camera->savedZoom());
+    info += QString("Pan (X, Y): (%1, %2)\n").arg(camera->savedPanX()).arg(camera->savedPanY());
+
+    m_textEdit->setText(info);
+}

src/DebugWindow.h

@@ -0,0 +1,30 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef DEBUGWINDOW_H
+#define DEBUGWINDOW_H
+
+#include <QDialog>
+
+class QTextEdit;
+class Camera;
+
+class DebugWindow : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit DebugWindow(QWidget *parent = nullptr);
+    ~DebugWindow();
+
+    void updateCameraInfo(const Camera* camera);
+
+private:
+    QTextEdit* m_textEdit;
+};
+
+#endif // DEBUGWINDOW_H

src/Document.cpp

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "Document.h"
 #include "Feature.h"
 #include "SketchFeature.h"

src/Document.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef DOCUMENT_H
 #define DOCUMENT_H
 

src/Feature.cpp

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "Feature.h"
 
 Feature::Feature(const QString& name) : m_name(name)

src/Feature.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef FEATURE_H
 #define FEATURE_H
 

src/FeatureBrowser.cpp

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "FeatureBrowser.h"
 #include "Document.h"
 #include "Feature.h"

src/FeatureBrowser.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef FEATUREBROWSER_H
 #define FEATUREBROWSER_H
 

src/LineTool.cpp

@@ -0,0 +1,864 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "LineTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QOpenGLShaderProgram>
+#include <QtMath>
+#include <optional>
+#include <gp_Ax2.hxx>
+#include <gp_Pnt2d.hxx>
+#include <gp_Dir2d.hxx>
+#include <gp_Vec2d.hxx>
+#include <gp_Vec.hxx>
+#include <ElCLib.hxx>
+
+LineTool::LineTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void LineTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes << "length" << "angle";
+    m_dimensionPropertyNames["length"] = "dimensionInput";
+    m_dimensionPropertyNames["angle"] = "angleInput";
+
+    m_viewport->setProperty("dimensionInput", "");
+    m_viewport->setProperty("angleInput", "");
+    m_viewport->setProperty("dimensionEditMode", "length");
+    m_viewport->setProperty("isChainedLine", false);
+}
+
+void LineTool::mousePressEvent(QMouseEvent *event)
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    gp_Pnt p;
+    QString dimInput = m_viewport->property("dimensionInput").toString();
+    QString angleInput = m_viewport->property("angleInput").toString();
+    bool lengthFromInput = false;
+    bool angleFromInput = false;
+    double inputLength = 0;
+    double inputAngleDegrees = 0;
+
+    if (m_isDefining) {
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+    }
+
+    if (m_isDefining && (lengthFromInput || angleFromInput)) {
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                const auto& xDir = plane.XDirection();
+                refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+            QVector3D currentMouseWorldPos = m_viewport->unproject(event->pos(), plane);
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+            gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+            gp_Pnt mousePnt(currentMouseWorldPos.x(), currentMouseWorldPos.y(), currentMouseWorldPos.z());
+            gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+            gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+            gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+            gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+            gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+            double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+            double refAngle = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            gp_Dir2d finalDir2d(cos(finalAngleRad), sin(finalAngleRad));
+            gp_Dir finalDir3d = ElCLib::To3d(plane, finalDir2d);
+            QVector3D finalDir(finalDir3d.X(), finalDir3d.Y(), finalDir3d.Z());
+            double lineLength;
+            if (lengthFromInput) lineLength = inputLength;
+            else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+        } else if (lengthFromInput) {
+            QVector3D currentMouseWorldPos = m_viewport->unproject(event->pos(), plane);
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                const auto& xDir = plane.XDirection();
+                worldPos = startPos + inputLength * QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+        }
+        p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+    } else {
+        if (m_viewport->isSnappingOrigin()) {
+            p = plane.Location();
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPosQ = m_viewport->unproject(event->pos(), plane);
+            gp_Pnt worldPos(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+
+            if (m_viewport->isSnappingHorizontal() || m_viewport->isSnappingVertical()) {
+                gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPos).Dot(plane.YDirection()));
+                gp_Pnt2d firstPoint2d(gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.XDirection()), gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.YDirection()));
+                if (m_viewport->isSnappingHorizontal()) {
+                    worldPos2d.SetY(firstPoint2d.Y());
+                } else { // vertical
+                    worldPos2d.SetX(firstPoint2d.X());
+                }
+                worldPos = ElCLib::To3d(plane, worldPos2d);
+            }
+            p = worldPos;
+        }
+    }
+
+    if (!m_isDefining) {
+        m_firstLinePoint = p;
+        m_isDefining = true;
+        m_viewport->setProperty("dimensionInput", QVariant(""));
+        m_viewport->setProperty("angleInput", QVariant(""));
+        m_viewport->setProperty("dimensionEditMode", "length");
+        m_viewport->setProperty("isChainedLine", false);
+    } else {
+        QVector3D start(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+        QVector3D end(p.X(), p.Y(), p.Z());
+        m_viewport->setProperty("previousLineDirection", QVariant::fromValue((end - start).normalized()));
+
+        m_viewport->addLine(m_firstLinePoint, p);
+        m_firstLinePoint = p;
+        m_viewport->setProperty("dimensionInput", QVariant(""));
+        m_viewport->setProperty("angleInput", QVariant(""));
+        m_viewport->setProperty("dimensionEditMode", "length");
+        m_viewport->setProperty("isChainedLine", true);
+    }
+}
+
+void LineTool::mouseMoveEvent(QMouseEvent *event)
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!m_isDefining || !currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    bool oldIsSnappingHorizontal = m_viewport->isSnappingHorizontal();
+    bool oldIsSnappingVertical = m_viewport->isSnappingVertical();
+    m_viewport->setSnappingHorizontal(false);
+    m_viewport->setSnappingVertical(false);
+
+    if (m_isDefining && !m_viewport->isSnappingOrigin() && !m_viewport->isSnappingVertex()) {
+        QVector3D worldPosQ = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+        gp_Pnt worldPos(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+        gp_Pnt startPos = m_firstLinePoint;
+
+        gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPos).Dot(plane.YDirection()));
+        gp_Pnt2d startPos2d(gp_Vec(plane.Location(), startPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPos).Dot(plane.YDirection()));
+        gp_Vec2d delta(startPos2d, worldPos2d);
+
+        if (delta.Magnitude() > 1e-6) {
+            const double snapAngleThreshold = qDegreesToRadians(2.0);
+            double angle = atan2(delta.Y(), delta.X());
+
+            if (qAbs(sin(angle)) < sin(snapAngleThreshold)) {
+                m_viewport->setSnappingHorizontal(true);
+            } else if (qAbs(cos(angle)) < sin(snapAngleThreshold)) {
+                m_viewport->setSnappingVertical(true);
+            }
+        }
+    }
+
+    if (oldIsSnappingHorizontal != m_viewport->isSnappingHorizontal() || oldIsSnappingVertical != m_viewport->isSnappingVertical()) {
+        m_viewport->update();
+    }
+}
+
+void LineTool::finalizeCreation()
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector3D worldPos;
+    QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+    // This is duplicated from paintGL to ensure consistent line creation
+    QString dimInput = m_viewport->property("dimensionInput").toString();
+    QString angleInput = m_viewport->property("angleInput").toString();
+    bool lengthFromInput = false;
+    bool angleFromInput = false;
+    double inputLength = 0;
+    double inputAngleDegrees = 0;
+
+    if (!dimInput.isEmpty()) {
+        bool ok;
+        inputLength = dimInput.toDouble(&ok);
+        if (ok) lengthFromInput = true;
+    }
+    if (!angleInput.isEmpty()) {
+        bool ok;
+        inputAngleDegrees = angleInput.toDouble(&ok);
+        if (ok) angleFromInput = true;
+    }
+
+    if (angleFromInput) {
+        QVector3D refDir;
+        if (m_viewport->property("isChainedLine").toBool()) {
+            refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+        } else {
+            const auto& xDir = plane.XDirection();
+            refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+        }
+        QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+        QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+        gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+        gp_Pnt mousePnt(currentMouseWorldPos.x(), currentMouseWorldPos.y(), currentMouseWorldPos.z());
+        gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+        gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+        gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+        gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+        gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+        double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+        double refAngle = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+        double relativeMouseAngle = mouseAngle - refAngle;
+        while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+        while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+        double snappedAngle = 0;
+        if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+            snappedAngle = inputAngleDegrees;
+        } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+            snappedAngle = 180.0 - inputAngleDegrees;
+        } else if (relativeMouseAngle < -90) { // Quadrant 3
+            snappedAngle = -180.0 + inputAngleDegrees;
+        } else { // Quadrant 4
+            snappedAngle = -inputAngleDegrees;
+        }
+        double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+        gp_Dir2d finalDir2d(cos(finalAngleRad), sin(finalAngleRad));
+        gp_Dir finalDir3d = ElCLib::To3d(plane, finalDir2d);
+        QVector3D finalDir(finalDir3d.X(), finalDir3d.Y(), finalDir3d.Z());
+        double lineLength;
+        if (lengthFromInput) lineLength = inputLength;
+        else {
+            lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+            if (lineLength < 0) lineLength = 0;
+        }
+        worldPos = startPos + lineLength * finalDir;
+    } else if (lengthFromInput) {
+        QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+        QVector3D dir = (currentMouseWorldPos - startPos);
+        if (dir.length() > 1e-6) {
+            dir.normalize();
+            worldPos = startPos + inputLength * dir;
+        } else {
+            const auto& xDir = plane.XDirection();
+            worldPos = startPos + inputLength * QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+        }
+    } else {
+        worldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+
+    QVector3D prevDir = (worldPos - startPos).normalized();
+    m_viewport->setProperty("previousLineDirection", QVariant::fromValue(prevDir));
+
+    m_viewport->addLine(m_firstLinePoint, p);
+    m_firstLinePoint = p;
+    m_viewport->setProperty("dimensionInput", QVariant(""));
+    m_viewport->setProperty("angleInput", QVariant(""));
+    m_viewport->setProperty("dimensionEditMode", "length");
+    m_viewport->setProperty("isChainedLine", true);
+}
+
+void LineTool::paintGL()
+{
+    if (m_isDefining) {
+        auto currentPlaneOpt = m_viewport->currentPlane();
+        if (!currentPlaneOpt) return;
+        const auto& plane = currentPlaneOpt.value();
+
+        QVector<GLfloat> vertices;
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+
+        QString dimInput = m_viewport->property("dimensionInput").toString();
+        QString angleInput = m_viewport->property("angleInput").toString();
+        bool lengthFromInput = false;
+        bool angleFromInput = false;
+        double inputLength = 0;
+        double inputAngleDegrees = 0;
+
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                const auto& xDir = plane.XDirection();
+                refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+            gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+            gp_Pnt mousePnt(currentMouseWorldPos.x(), currentMouseWorldPos.y(), currentMouseWorldPos.z());
+            gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+            gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+            gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+            gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+            gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+            double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+            double refAngle = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            gp_Dir2d finalDir2d(cos(finalAngleRad), sin(finalAngleRad));
+            gp_Dir finalDir3d = ElCLib::To3d(plane, finalDir2d);
+            QVector3D finalDir(finalDir3d.X(), finalDir3d.Y(), finalDir3d.Z());
+
+            double lineLength;
+            if (lengthFromInput) {
+                lineLength = inputLength;
+            } else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                 if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+
+        } else if (lengthFromInput) {
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                const auto& xDir = plane.XDirection();
+                worldPos = startPos + inputLength * QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+        } else {
+            worldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            gp_Pnt worldPosPnt(worldPos.x(), worldPos.y(), worldPos.z());
+
+            if (m_viewport->isSnappingOrigin()) {
+                worldPosPnt = plane.Location();
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPosPnt = m_viewport->snapVertex();
+            } else if (m_viewport->isSnappingHorizontal() || m_viewport->isSnappingVertical()) {
+                gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPosPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPosPnt).Dot(plane.YDirection()));
+                gp_Pnt2d firstPoint2d(gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.XDirection()), gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.YDirection()));
+                if (m_viewport->isSnappingHorizontal()) {
+                    worldPos2d.SetY(firstPoint2d.Y());
+                } else { // vertical
+                    worldPos2d.SetX(firstPoint2d.X());
+                }
+                worldPosPnt = ElCLib::To3d(plane, worldPos2d);
+            }
+            worldPos.setX(worldPosPnt.X()); worldPos.setY(worldPosPnt.Y()); worldPos.setZ(worldPosPnt.Z());
+        }
+
+        vertices << m_firstLinePoint.X() << m_firstLinePoint.Y() << m_firstLinePoint.Z();
+        vertices << worldPos.x() << worldPos.y() << worldPos.z();
+
+        m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+        m_viewport->vbo().bind();
+        m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+        glDrawArrays(GL_LINES, 0, 2);
+
+        // Draw dimension line
+        QVector3D lineVec = worldPos - startPos;
+        float lineLength = lineVec.length();
+
+        if (lineLength > 1e-6) {
+            double refAngle, lineAngle, angleDiff;
+            {
+                QVector3D refDir;
+                if (m_viewport->property("isChainedLine").toBool()) {
+                    refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+                } else {
+                    const auto& xDir = plane.XDirection();
+                    refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+                }
+
+                if (angleFromInput) {
+                    QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+                    QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+                    gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+                    gp_Pnt mousePnt(currentMouseWorldPos.x(), currentMouseWorldPos.y(), currentMouseWorldPos.z());
+                    gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+                    gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+                    gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+                    gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+                    gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+                    double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+                    double refAngleForQuadrant = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+
+                    double relativeMouseAngle = mouseAngle - refAngleForQuadrant;
+                    while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+                    while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+                    if (relativeMouseAngle >= 90 || relativeMouseAngle < -90) {
+                        refDir = -refDir;
+                    }
+                } else {
+                    if (m_viewport->property("isChainedLine").toBool()) {
+                        refDir = -refDir;
+                    }
+                }
+
+                gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+                gp_Dir lineDirGp(lineVec.x(), lineVec.y(), lineVec.z());
+
+                gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+                gp_Dir2d lineDir2d(lineDirGp.Dot(plane.XDirection()), lineDirGp.Dot(plane.YDirection()));
+
+                refAngle = atan2(refDir2d.Y(), refDir2d.X());
+                lineAngle = atan2(lineDir2d.Y(), lineDir2d.X());
+
+                angleDiff = lineAngle - refAngle;
+                while (angleDiff <= -M_PI) angleDiff += 2 * M_PI;
+                while (angleDiff > M_PI) angleDiff -= 2 * M_PI;
+                lineAngle = refAngle + angleDiff;
+            }
+
+            vertices.clear();
+
+            gp_Dir lineDirGp(lineVec.x(), lineVec.y(), lineVec.z());
+            gp_Dir2d lineDir2d(lineDirGp.Dot(plane.XDirection()), lineDirGp.Dot(plane.YDirection()));
+            gp_Dir2d perpDir2d(-lineDir2d.Y(), lineDir2d.X());
+            gp_Dir perpDir3d = ElCLib::To3d(plane, perpDir2d);
+            QVector3D perpVec(perpDir3d.X(), perpDir3d.Y(), perpDir3d.Z());
+
+            if (angleDiff < 0) {
+                perpVec = -perpVec;
+            }
+
+            float offset = 0.05f * -m_viewport->camera()->zoom();
+            QVector3D dimStart = startPos + offset * perpVec;
+            QVector3D dimEnd = worldPos + offset * perpVec;
+
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+
+            float arrowLength = 0.02f * -m_viewport->camera()->zoom();
+            float arrowWidth = 0.005f * -m_viewport->camera()->zoom();
+            QVector3D lineDir = lineVec.normalized();
+
+            QVector3D arrow_base_end = dimEnd - arrowLength * lineDir;
+            QVector3D arrowP1_end = arrow_base_end + arrowWidth * perpVec;
+            QVector3D arrowP2_end = arrow_base_end - arrowWidth * perpVec;
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+            vertices << arrowP1_end.x() << arrowP1_end.y() << arrowP1_end.z();
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+            vertices << arrowP2_end.x() << arrowP2_end.y() << arrowP2_end.z();
+
+            QVector3D arrow_base_start = dimStart + arrowLength * lineDir;
+            QVector3D arrowP1_start = arrow_base_start + arrowWidth * perpVec;
+            QVector3D arrowP2_start = arrow_base_start - arrowWidth * perpVec;
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << arrowP1_start.x() << arrowP1_start.y() << arrowP1_start.z();
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << arrowP2_start.x() << arrowP2_start.y() << arrowP2_start.z();
+
+            m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(0.7f, 0.7f, 0.7f, 1.0f));
+            glLineWidth(1.0f);
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, vertices.size() / 3);
+            glLineWidth(2.0f);
+
+            // Draw angle dimension
+            vertices.clear();
+            const int numSegments = 30;
+            const float radius = 0.1f * -m_viewport->camera()->zoom();
+            for (int i = 0; i <= numSegments; ++i) {
+                double angle = refAngle + (lineAngle - refAngle) * i / numSegments;
+                QVector3D p;
+                const auto& xDir = plane.XDirection();
+                const auto& yDir = plane.YDirection();
+                QVector3D u_axis(xDir.X(), xDir.Y(), xDir.Z());
+                QVector3D v_axis(yDir.X(), yDir.Y(), yDir.Z());
+                p = startPos + radius * (cos(angle) * u_axis + sin(angle) * v_axis);
+                vertices << p.x() << p.y() << p.z();
+            }
+            glLineWidth(1.0f);
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 3);
+
+            // Arrowheads for arc
+            QVector<GLfloat> arrowVertices;
+            float arcArrowLength = 0.02f * -m_viewport->camera()->zoom();
+            float arcArrowWidth = 0.005f * -m_viewport->camera()->zoom();
+
+            double sign = (angleDiff >= 0) ? 1.0 : -1.0;
+
+            // End arrowhead
+            QVector3D endPoint(vertices[vertices.size()-3], vertices[vertices.size()-2], vertices[vertices.size()-1]);
+            double endAngle = lineAngle;
+            const auto& xDir = plane.XDirection();
+            const auto& yDir = plane.YDirection();
+            QVector3D u_axis(xDir.X(), xDir.Y(), xDir.Z());
+            QVector3D v_axis(yDir.X(), yDir.Y(), yDir.Z());
+            QVector3D radialDir_end, tangentDir_end;
+            radialDir_end = cos(endAngle) * u_axis + sin(endAngle) * v_axis;
+            tangentDir_end = -sin(endAngle) * u_axis + cos(endAngle) * v_axis;
+            QVector3D arc_arrow_base_end = endPoint - sign * arcArrowLength * tangentDir_end;
+            QVector3D arc_arrowP1_end = arc_arrow_base_end + arcArrowWidth * radialDir_end;
+            QVector3D arc_arrowP2_end = arc_arrow_base_end - arcArrowWidth * radialDir_end;
+            arrowVertices << endPoint.x() << endPoint.y() << endPoint.z() << arc_arrowP1_end.x() << arc_arrowP1_end.y() << arc_arrowP1_end.z();
+            arrowVertices << endPoint.x() << endPoint.y() << endPoint.z() << arc_arrowP2_end.x() << arc_arrowP2_end.y() << arc_arrowP2_end.z();
+
+            // Start arrowhead
+            QVector3D startPoint(vertices[0], vertices[1], vertices[2]);
+            double startAngle = refAngle;
+            QVector3D radialDir_start, tangentDir_start;
+            radialDir_start = cos(startAngle) * u_axis + sin(startAngle) * v_axis;
+            tangentDir_start = -sin(startAngle) * u_axis + cos(startAngle) * v_axis;
+            QVector3D arc_arrow_base_start = startPoint + sign * arcArrowLength * tangentDir_start;
+            QVector3D arc_arrowP1_start = arc_arrow_base_start + arcArrowWidth * radialDir_start;
+            QVector3D arc_arrowP2_start = arc_arrow_base_start - arcArrowWidth * radialDir_start;
+            arrowVertices << startPoint.x() << startPoint.y() << startPoint.z() << arc_arrowP1_start.x() << arc_arrowP1_start.y() << arc_arrowP1_start.z();
+            arrowVertices << startPoint.x() << startPoint.y() << startPoint.z() << arc_arrowP2_start.x() << arc_arrowP2_start.y() << arc_arrowP2_start.z();
+
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(arrowVertices.constData(), arrowVertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, arrowVertices.size() / 3);
+            glLineWidth(2.0f);
+        }
+
+        if (!lengthFromInput && !angleFromInput && (m_viewport->isSnappingHorizontal() || m_viewport->isSnappingVertical())) {
+            vertices.clear();
+            QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+            QVector3D midPoint = (startPos + worldPos) / 2.0;
+            const float indicatorSize = 0.02f * -m_viewport->camera()->zoom();
+            const float indicatorOffset = 0.02f * -m_viewport->camera()->zoom();
+            const auto& xDir = plane.XDirection();
+            const auto& yDir = plane.YDirection();
+            QVector3D u_axis(xDir.X(), xDir.Y(), xDir.Z());
+            QVector3D v_axis(yDir.X(), yDir.Y(), yDir.Z());
+
+            QVector3D p1, p2;
+            if (m_viewport->isSnappingHorizontal()) {
+                p1 = midPoint - indicatorSize * v_axis + indicatorOffset * u_axis;
+                p2 = midPoint + indicatorSize * v_axis + indicatorOffset * u_axis;
+            } else { // m_isSnappingVertical
+                p1 = midPoint - indicatorSize * u_axis + indicatorOffset * v_axis;
+                p2 = midPoint + indicatorSize * u_axis + indicatorOffset * v_axis;
+            }
+            vertices << p1.x() << p1.y() << p1.z();
+            vertices << p2.x() << p2.y() << p2.z();
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, 2);
+        }
+    }
+}
+
+void LineTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    if (m_isDefining) {
+        auto currentPlaneOpt = m_viewport->currentPlane();
+        if (!currentPlaneOpt) return;
+        const auto& plane = currentPlaneOpt.value();
+
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+        QString dimText;
+        QString angleText;
+
+        QString dimInput = m_viewport->property("dimensionInput").toString();
+        QString angleInput = m_viewport->property("angleInput").toString();
+        bool lengthFromInput = false;
+        bool angleFromInput = false;
+        double inputLength = 0;
+        double inputAngleDegrees = 0;
+        double lineLength = 0;
+
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                const auto& xDir = plane.XDirection();
+                refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+            gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+            gp_Pnt mousePnt(currentMouseWorldPos.x(), currentMouseWorldPos.y(), currentMouseWorldPos.z());
+            gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+            gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+            gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+            gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+            gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+            double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+            double refAngle = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            gp_Dir2d finalDir2d(cos(finalAngleRad), sin(finalAngleRad));
+            gp_Dir finalDir3d = ElCLib::To3d(plane, finalDir2d);
+            QVector3D finalDir(finalDir3d.X(), finalDir3d.Y(), finalDir3d.Z());
+
+            if (lengthFromInput) {
+                lineLength = inputLength;
+            } else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                 if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+
+        } else if (lengthFromInput) {
+            lineLength = inputLength;
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                const auto& xDir = plane.XDirection();
+                worldPos = startPos + inputLength * QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+        } else {
+            worldPos = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            gp_Pnt worldPosPnt(worldPos.x(), worldPos.y(), worldPos.z());
+
+            if (m_viewport->isSnappingOrigin()) {
+                worldPosPnt = plane.Location();
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPosPnt = m_viewport->snapVertex();
+            } else if (m_viewport->isSnappingHorizontal() || m_viewport->isSnappingVertical()) {
+                gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPosPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPosPnt).Dot(plane.YDirection()));
+                gp_Pnt2d firstPoint2d(gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.XDirection()), gp_Vec(plane.Location(), m_firstLinePoint).Dot(plane.YDirection()));
+                if (m_viewport->isSnappingHorizontal()) {
+                    worldPos2d.SetY(firstPoint2d.Y());
+                } else { // vertical
+                    worldPos2d.SetX(firstPoint2d.X());
+                }
+                worldPosPnt = ElCLib::To3d(plane, worldPos2d);
+            }
+            worldPos.setX(worldPosPnt.X()); worldPos.setY(worldPosPnt.Y()); worldPos.setZ(worldPosPnt.Z());
+            lineLength = (worldPos - startPos).length();
+        }
+
+        QVector3D lineVec = worldPos - startPos;
+        if (lineVec.length() > 1e-6) {
+            double refAngle, lineAngle;
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                const auto& xDir = plane.XDirection();
+                refDir = QVector3D(xDir.X(), xDir.Y(), xDir.Z());
+            }
+
+            QVector3D currentMouseWorldPosForText = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+            QVector3D mouseVecForText = currentMouseWorldPosForText - startPos;
+
+            if (angleFromInput) {
+                if (mouseVecForText.length() > 1e-6) {
+                    gp_Pnt startPnt(startPos.x(), startPos.y(), startPos.z());
+                    gp_Pnt mousePnt(currentMouseWorldPosForText.x(), currentMouseWorldPosForText.y(), currentMouseWorldPosForText.z());
+                    gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+
+                    gp_Pnt2d startPnt2d(gp_Vec(plane.Location(), startPnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPnt).Dot(plane.YDirection()));
+                    gp_Pnt2d mousePnt2d(gp_Vec(plane.Location(), mousePnt).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePnt).Dot(plane.YDirection()));
+                    gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+
+                    gp_Vec2d mouseVec2d(startPnt2d, mousePnt2d);
+                    double mouseAngle = qRadiansToDegrees(atan2(mouseVec2d.Y(), mouseVec2d.X()));
+                    double refAngleForQuadrant = qRadiansToDegrees(atan2(refDir2d.Y(), refDir2d.X()));
+
+                    double relativeMouseAngle = mouseAngle - refAngleForQuadrant;
+                    while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+                    while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+                    if (relativeMouseAngle >= 90 || relativeMouseAngle < -90) {
+                        refDir = -refDir;
+                    }
+                }
+            } else {
+                if (m_viewport->property("isChainedLine").toBool()) {
+                    refDir = -refDir;
+                }
+            }
+
+            gp_Dir refDirGp(refDir.x(), refDir.y(), refDir.z());
+            gp_Dir lineDirGp(lineVec.x(), lineVec.y(), lineVec.z());
+
+            gp_Dir2d refDir2d(refDirGp.Dot(plane.XDirection()), refDirGp.Dot(plane.YDirection()));
+            gp_Dir2d lineDir2d(lineDirGp.Dot(plane.XDirection()), lineDirGp.Dot(plane.YDirection()));
+
+            refAngle = atan2(refDir2d.Y(), refDir2d.X());
+            lineAngle = atan2(lineDir2d.Y(), lineDir2d.X());
+
+            double angleDiff = lineAngle - refAngle;
+            while (angleDiff <= -M_PI) angleDiff += 2 * M_PI;
+            while (angleDiff > M_PI) angleDiff -= 2 * M_PI;
+            lineAngle = refAngle + angleDiff;
+
+            gp_Dir2d perpDir2d(-lineDir2d.Y(), lineDir2d.X());
+            gp_Dir perpDir3d = ElCLib::To3d(plane, perpDir2d);
+            QVector3D perpVec(perpDir3d.X(), perpDir3d.Y(), perpDir3d.Z());
+
+            if (angleDiff < 0) {
+                perpVec = -perpVec;
+            }
+
+            float offset = 0.05f * -m_viewport->camera()->zoom();
+            QVector3D dimStart = startPos + offset * perpVec;
+            QVector3D dimEnd = worldPos + offset * perpVec;
+            QVector3D textPos3D = (dimStart + dimEnd) / 2.0f + 0.015f * -m_viewport->camera()->zoom() * perpVec;
+
+            QVector3D screenPos = m_viewport->project(textPos3D, modelView, projection, m_viewport->rect());
+
+            painter.setRenderHint(QPainter::Antialiasing);
+            QFontMetrics fm(painter.font());
+
+            if (screenPos.z() < 1.0f) {
+                dimText = lengthFromInput ? dimInput : QString::number(lineLength, 'f', 2);
+
+                QRect textRect = fm.boundingRect(dimText + "_");
+                textRect.moveCenter(screenPos.toPoint());
+
+                if (m_viewport->property("dimensionEditMode").toString() == "length") {
+                    painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+                } else {
+                    painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+                }
+                painter.setPen(Qt::white);
+                painter.drawText(textRect, Qt::AlignCenter, dimText);
+            }
+
+            // Angle dimension text
+            double angleDiffDegrees = qRadiansToDegrees(angleDiff);
+            while (angleDiffDegrees <= -180.0) angleDiffDegrees += 360.0;
+            while (angleDiffDegrees > 180.0) angleDiffDegrees -= 360.0;
+
+            angleText = angleFromInput ? angleInput : QString::number(qAbs(angleDiffDegrees), 'f', 1) + QChar(0x00B0);
+
+            const float radius = 0.1f * -m_viewport->camera()->zoom();
+            double midAngle = refAngle + (lineAngle - refAngle) / 2.0;
+            QVector3D textPos3DAngle;
+            float textOffset = 0.035f * -m_viewport->camera()->zoom();
+
+            const auto& xDir = plane.XDirection();
+            const auto& yDir = plane.YDirection();
+            QVector3D u_axis(xDir.X(), xDir.Y(), xDir.Z());
+            QVector3D v_axis(yDir.X(), yDir.Y(), yDir.Z());
+            textPos3DAngle = startPos + (radius + textOffset) * (cos(midAngle) * u_axis + sin(midAngle) * v_axis);
+
+            QVector3D screenPosAngle = m_viewport->project(textPos3DAngle, modelView, projection, m_viewport->rect());
+            if (screenPosAngle.z() < 1.0f) {
+                QRect angleTextRect = fm.boundingRect(angleText + "_");
+                angleTextRect.moveCenter(screenPosAngle.toPoint());
+                if (m_viewport->property("dimensionEditMode").toString() == "angle") {
+                    painter.fillRect(angleTextRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+                } else {
+                    painter.fillRect(angleTextRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+                }
+                painter.setPen(Qt::white);
+                painter.drawText(angleTextRect, Qt::AlignCenter, angleText);
+            }
+        }
+    }
+}

src/LineTool.h

@@ -0,0 +1,35 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef LINETOOL_H
+#define LINETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class LineTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit LineTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_firstLinePoint;
+};
+
+#endif // LINETOOL_H

src/MainWindow.cpp

@@ -1,9 +1,18 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "MainWindow.h"
 #include "ViewportWidget.h"
 #include "Document.h"
 #include "SketchFeature.h"
 #include "Feature.h"
 #include "ApplicationController.h"
+#include "DebugWindow.h"
+#include "Camera.h"
 
 #include <QMenuBar>
 #include <QMenu>
@@ -17,11 +26,15 @@
 #include <QIcon>
 #include <QInputDialog>
 #include <QStringList>
+#include <QKeyEvent>
+#include <QApplication>
+#include <QProcessEnvironment>
 
 MainWindow::MainWindow(ApplicationController* appController, QWidget *parent)
     : QMainWindow(parent)
     , m_appController(appController)
 {
+    qApp->installEventFilter(this);
     setWindowTitle("OpenCAD");
     resize(1920, 1080);
 
@@ -38,6 +51,10 @@ MainWindow::MainWindow(ApplicationController* appController, QWidget *parent)
     QAction *saveAsAction = fileMenu->addAction("Save &As...");
     connect(saveAsAction, &QAction::triggered, this, &MainWindow::saveAs);
 
+    QMenu *helpMenu = menuBar()->addMenu("&Help");
+    QAction *debugAction = helpMenu->addAction("&Debug");
+    connect(debugAction, &QAction::triggered, this, &MainWindow::showDebugWindow);
+
 
     QToolBar* mainToolBar = addToolBar("Main Toolbar");
     mainToolBar->setMovable(false);
@@ -143,9 +160,18 @@ MainWindow::MainWindow(ApplicationController* appController, QWidget *parent)
     connect(m_appController, &ApplicationController::planeSelectionModeStarted, m_viewport, &ViewportWidget::onPlaneSelectionModeStarted);
 
     connect(m_viewport, &ViewportWidget::lineAdded, m_appController, &ApplicationController::addLine);
+    connect(m_viewport, &ViewportWidget::rectangleAdded, m_appController, &ApplicationController::addRectangle);
+    connect(m_viewport, &ViewportWidget::circleAdded, m_appController, &ApplicationController::addCircle);
     connect(m_viewport, &ViewportWidget::planeSelected, m_appController, &ApplicationController::onPlaneSelected);
     connect(m_viewport, &ViewportWidget::toolDeactivated, m_appController, [this]() { m_appController->setActiveTool(ApplicationController::ToolType::None); });
 
+    connect(m_viewport->camera(), &Camera::cameraChanged, this, &MainWindow::updateDebugInfo);
+
+    m_debugWindow = new DebugWindow(this);
+    if (QProcessEnvironment::systemEnvironment().value("DEBUG") == "true") {
+        showDebugWindow();
+    }
+
     updateWindowTitle(QString());
 }
 
@@ -179,6 +205,17 @@ bool MainWindow::saveAs()
     return m_appController->saveDocumentAs();
 }
 
+void MainWindow::showDebugWindow()
+{
+    updateDebugInfo();
+    m_debugWindow->show();
+}
+
+void MainWindow::updateDebugInfo()
+{
+    m_debugWindow->updateCameraInfo(m_viewport->camera());
+}
+
 void MainWindow::enterSketchMode()
 {
     m_tabWidget->removeTab(m_tabWidget->indexOf(m_toolsTab));
@@ -204,3 +241,19 @@ void MainWindow::updateWindowTitle(const QString& filePath)
         shownName = "Untitled";
     setWindowTitle(tr("%1[*] - %2").arg(QFileInfo(shownName).fileName(), tr("OpenCAD")));
 }
+
+bool MainWindow::eventFilter(QObject *watched, QEvent *event)
+{
+    if (m_appController->activeTool() != ApplicationController::ToolType::None && event->type() == QEvent::KeyPress) {
+        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
+        if (keyEvent->key() == Qt::Key_Tab || keyEvent->key() == Qt::Key_Backtab) {
+            if (watched == m_viewport) {
+                return false; // Let the viewport handle its own event
+            }
+            // Forward event to viewport and consume it
+            QApplication::sendEvent(m_viewport, keyEvent);
+            return true;
+        }
+    }
+    return QMainWindow::eventFilter(watched, event);
+}

src/MainWindow.h

@@ -1,14 +1,23 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
 #include <QMainWindow>
 
+class QEvent;
 class ViewportWidget;
 class Document;
 class Feature;
 class QTabWidget;
 class QWidget;
 class ApplicationController;
+class DebugWindow;
 
 class MainWindow : public QMainWindow
 {
@@ -25,13 +34,20 @@ private slots:
     void createSketch();
     void saveSketch();
 
+    void showDebugWindow();
+    void updateDebugInfo();
+
     void enterSketchMode();
     void exitSketchMode();
     void updateWindowTitle(const QString& filePath);
 
+protected:
+    bool eventFilter(QObject *watched, QEvent *event) override;
+
 private:
     ApplicationController* m_appController;
     ViewportWidget *m_viewport;
+    DebugWindow* m_debugWindow;
 
     QTabWidget *m_tabWidget;
     QWidget *m_solidTab;

src/RectangleTool.cpp

@@ -0,0 +1,363 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "RectangleTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QVector>
+#include <QOpenGLShaderProgram>
+#include <cmath>
+#include <QtMath>
+#include <optional>
+#include <gp_Ax2.hxx>
+#include <gp_Pnt2d.hxx>
+#include <gp_Vec.hxx>
+#include <ElCLib.hxx>
+
+RectangleTool::RectangleTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void RectangleTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes << "height" << "width";
+    m_dimensionPropertyNames["height"] = "heightInput";
+    m_dimensionPropertyNames["width"] = "widthInput";
+
+    m_viewport->setProperty("widthInput", "");
+    m_viewport->setProperty("heightInput", "");
+    m_viewport->setProperty("dimensionEditMode", "height");
+}
+
+void RectangleTool::mousePressEvent(QMouseEvent *event)
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    gp_Pnt p;
+    if (!m_isDefining) {
+        if (m_viewport->isSnappingOrigin()) {
+            p = plane.Location();
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPos = m_viewport->unproject(event->pos(), plane);
+            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        }
+        m_firstRectanglePoint = p;
+        m_isDefining = true;
+        m_viewport->setProperty("widthInput", "");
+        m_viewport->setProperty("heightInput", "");
+        m_viewport->setProperty("dimensionEditMode", "height");
+    } else {
+        QVector3D worldPosQ;
+        gp_Pnt startPos = m_firstRectanglePoint;
+
+        QString widthInput = m_viewport->property("widthInput").toString();
+        QString heightInput = m_viewport->property("heightInput").toString();
+        bool widthFromInput = false, heightFromInput = false;
+        double inputWidth = 0, inputHeight = 0;
+
+        if (!widthInput.isEmpty()) {
+            bool ok;
+            inputWidth = widthInput.toDouble(&ok);
+            if (ok) widthFromInput = true;
+        }
+        if (!heightInput.isEmpty()) {
+            bool ok;
+            inputHeight = heightInput.toDouble(&ok);
+            if (ok) heightFromInput = true;
+        }
+
+        if (widthFromInput || heightFromInput) {
+            QVector3D mousePosQ = m_viewport->unproject(event->pos(), plane);
+            gp_Pnt mousePos(mousePosQ.x(), mousePosQ.y(), mousePosQ.z());
+
+            gp_Pnt2d startPos2d(gp_Vec(plane.Location(), startPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPos).Dot(plane.YDirection()));
+            gp_Pnt2d mousePos2d(gp_Vec(plane.Location(), mousePos).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePos).Dot(plane.YDirection()));
+
+            double current_w = qAbs(mousePos2d.X() - startPos2d.X());
+            double current_h = qAbs(mousePos2d.Y() - startPos2d.Y());
+
+            double rect_w = widthFromInput ? inputWidth : current_w;
+            double rect_h = heightFromInput ? inputHeight : current_h;
+
+            int signX = (mousePos2d.X() >= startPos2d.X()) ? 1 : -1;
+            int signY = (mousePos2d.Y() >= startPos2d.Y()) ? 1 : -1;
+
+            gp_Pnt2d endPos2d(startPos2d.X() + signX * rect_w, startPos2d.Y() + signY * rect_h);
+            gp_Pnt endPos3d = ElCLib::To3d(plane, endPos2d);
+            worldPosQ = QVector3D(endPos3d.X(), endPos3d.Y(), endPos3d.Z());
+        } else {
+            if (m_viewport->isSnappingOrigin()) {
+                const auto& origin = plane.Location();
+                worldPosQ.setX(origin.X()); worldPosQ.setY(origin.Y()); worldPosQ.setZ(origin.Z());
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPosQ = QVector3D(m_viewport->snapVertex().X(), m_viewport->snapVertex().Y(), m_viewport->snapVertex().Z());
+            } else {
+                worldPosQ = m_viewport->unproject(event->pos(), plane);
+            }
+        }
+        p.SetCoord(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+        emit m_viewport->rectangleAdded(m_firstRectanglePoint, p);
+        deactivate();
+    }
+}
+
+void RectangleTool::mouseMoveEvent(QMouseEvent *event)
+{
+    // To be implemented
+}
+
+void RectangleTool::finalizeCreation()
+{
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector3D worldPosQ;
+    gp_Pnt startPos = m_firstRectanglePoint;
+
+    QString widthInput = m_viewport->property("widthInput").toString();
+    QString heightInput = m_viewport->property("heightInput").toString();
+    bool widthFromInput = false, heightFromInput = false;
+    double inputWidth = 0, inputHeight = 0;
+
+    if (!widthInput.isEmpty()) {
+        bool ok;
+        inputWidth = widthInput.toDouble(&ok);
+        if (ok) widthFromInput = true;
+    }
+    if (!heightInput.isEmpty()) {
+        bool ok;
+        inputHeight = heightInput.toDouble(&ok);
+        if (ok) heightFromInput = true;
+    }
+
+    if (widthFromInput || heightFromInput) {
+        QVector3D mousePosQ = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+        gp_Pnt mousePos(mousePosQ.x(), mousePosQ.y(), mousePosQ.z());
+
+        gp_Pnt2d startPos2d(gp_Vec(plane.Location(), startPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPos).Dot(plane.YDirection()));
+        gp_Pnt2d mousePos2d(gp_Vec(plane.Location(), mousePos).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePos).Dot(plane.YDirection()));
+
+        double current_w = qAbs(mousePos2d.X() - startPos2d.X());
+        double current_h = qAbs(mousePos2d.Y() - startPos2d.Y());
+
+        double rect_w = widthFromInput ? inputWidth : current_w;
+        double rect_h = heightFromInput ? inputHeight : current_h;
+
+        int signX = (mousePos2d.X() >= startPos2d.X()) ? 1 : -1;
+        int signY = (mousePos2d.Y() >= startPos2d.Y()) ? 1 : -1;
+
+        gp_Pnt2d endPos2d(startPos2d.X() + signX * rect_w, startPos2d.Y() + signY * rect_h);
+        gp_Pnt endPos3d = ElCLib::To3d(plane, endPos2d);
+        worldPosQ = QVector3D(endPos3d.X(), endPos3d.Y(), endPos3d.Z());
+    } else {
+        worldPosQ = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+
+    emit m_viewport->rectangleAdded(m_firstRectanglePoint, p);
+    deactivate();
+}
+
+void RectangleTool::paintGL()
+{
+    if (!m_isDefining) return;
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector<GLfloat> vertices;
+    QVector3D worldPosQ;
+    gp_Pnt startPos = m_firstRectanglePoint;
+
+    QString widthInput = m_viewport->property("widthInput").toString();
+    QString heightInput = m_viewport->property("heightInput").toString();
+    bool widthFromInput = false;
+    bool heightFromInput = false;
+    double inputWidth = 0, inputHeight = 0;
+
+    if (!widthInput.isEmpty()) {
+        bool ok;
+        inputWidth = widthInput.toDouble(&ok);
+        if (ok) widthFromInput = true;
+    }
+    if (!heightInput.isEmpty()) {
+        bool ok;
+        inputHeight = heightInput.toDouble(&ok);
+        if (ok) heightFromInput = true;
+    }
+
+    QVector3D mousePosQ = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    gp_Pnt mousePos(mousePosQ.x(), mousePosQ.y(), mousePosQ.z());
+
+    if (widthFromInput || heightFromInput) {
+        gp_Pnt2d startPos2d(gp_Vec(plane.Location(), startPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), startPos).Dot(plane.YDirection()));
+        gp_Pnt2d mousePos2d(gp_Vec(plane.Location(), mousePos).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePos).Dot(plane.YDirection()));
+
+        double current_w = qAbs(mousePos2d.X() - startPos2d.X());
+        double current_h = qAbs(mousePos2d.Y() - startPos2d.Y());
+
+        double rect_w = widthFromInput ? inputWidth : current_w;
+        double rect_h = heightFromInput ? inputHeight : current_h;
+
+        int signX = (mousePos2d.X() >= startPos2d.X()) ? 1 : -1;
+        int signY = (mousePos2d.Y() >= startPos2d.Y()) ? 1 : -1;
+
+        gp_Pnt2d endPos2d(startPos2d.X() + signX * rect_w, startPos2d.Y() + signY * rect_h);
+        gp_Pnt endPos3d = ElCLib::To3d(plane, endPos2d);
+        worldPosQ = QVector3D(endPos3d.X(), endPos3d.Y(), endPos3d.Z());
+    } else {
+        worldPosQ = mousePosQ;
+        if (m_viewport->isSnappingOrigin()) {
+            const auto& origin = plane.Location();
+            worldPosQ.setX(origin.X()); worldPosQ.setY(origin.Y()); worldPosQ.setZ(origin.Z());
+        } else if (m_viewport->isSnappingVertex()) {
+            worldPosQ.setX(m_viewport->snapVertex().X()); worldPosQ.setY(m_viewport->snapVertex().Y()); worldPosQ.setZ(m_viewport->snapVertex().Z());
+        }
+    }
+
+    gp_Pnt p1_3d = startPos;
+    gp_Pnt p3_3d(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+    gp_Pnt2d p1_2d(gp_Vec(plane.Location(), p1_3d).Dot(plane.XDirection()), gp_Vec(plane.Location(), p1_3d).Dot(plane.YDirection()));
+    gp_Pnt2d p3_2d(gp_Vec(plane.Location(), p3_3d).Dot(plane.XDirection()), gp_Vec(plane.Location(), p3_3d).Dot(plane.YDirection()));
+
+    gp_Pnt2d p2_2d(p3_2d.X(), p1_2d.Y());
+    gp_Pnt2d p4_2d(p1_2d.X(), p3_2d.Y());
+
+    gp_Pnt p2_3d = ElCLib::To3d(plane, p2_2d);
+    gp_Pnt p4_3d = ElCLib::To3d(plane, p4_2d);
+
+    vertices << p1_3d.X() << p1_3d.Y() << p1_3d.Z();
+    vertices << p2_3d.X() << p2_3d.Y() << p2_3d.Z();
+    vertices << p2_3d.X() << p2_3d.Y() << p2_3d.Z();
+    vertices << p3_3d.X() << p3_3d.Y() << p3_3d.Z();
+    vertices << p3_3d.X() << p3_3d.Y() << p3_3d.Z();
+    vertices << p4_3d.X() << p4_3d.Y() << p4_3d.Z();
+    vertices << p4_3d.X() << p4_3d.Y() << p4_3d.Z();
+    vertices << p1_3d.X() << p1_3d.Y() << p1_3d.Z();
+
+    m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+    m_viewport->vbo().bind();
+    m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+    glDrawArrays(GL_LINES, 0, 8);
+}
+
+void RectangleTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    if (!m_isDefining) return;
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) return;
+    const auto& plane = currentPlaneOpt.value();
+
+    QVector3D worldPosQ;
+    gp_Pnt p1_3d = m_firstRectanglePoint;
+
+    QString widthInput = m_viewport->property("widthInput").toString();
+    QString heightInput = m_viewport->property("heightInput").toString();
+    bool widthFromInput = false;
+    bool heightFromInput = false;
+    double inputWidth = 0, inputHeight = 0;
+
+    if (!widthInput.isEmpty()) {
+        bool ok;
+        inputWidth = widthInput.toDouble(&ok);
+        if (ok) widthFromInput = true;
+    }
+    if (!heightInput.isEmpty()) {
+        bool ok;
+        inputHeight = heightInput.toDouble(&ok);
+        if (ok) heightFromInput = true;
+    }
+
+    QVector3D mousePosQ = m_viewport->unproject(m_viewport->currentMousePos(), plane);
+    gp_Pnt mousePos(mousePosQ.x(), mousePosQ.y(), mousePosQ.z());
+
+    if (widthFromInput || heightFromInput) {
+        gp_Pnt2d startPos2d(gp_Vec(plane.Location(), p1_3d).Dot(plane.XDirection()), gp_Vec(plane.Location(), p1_3d).Dot(plane.YDirection()));
+        gp_Pnt2d mousePos2d(gp_Vec(plane.Location(), mousePos).Dot(plane.XDirection()), gp_Vec(plane.Location(), mousePos).Dot(plane.YDirection()));
+
+        double current_w = qAbs(mousePos2d.X() - startPos2d.X());
+        double current_h = qAbs(mousePos2d.Y() - startPos2d.Y());
+
+        double rect_w = widthFromInput ? inputWidth : current_w;
+        double rect_h = heightFromInput ? inputHeight : current_h;
+        int signX = (mousePos2d.X() >= startPos2d.X()) ? 1 : -1;
+        int signY = (mousePos2d.Y() >= startPos2d.Y()) ? 1 : -1;
+
+        gp_Pnt2d endPos2d(startPos2d.X() + signX * rect_w, startPos2d.Y() + signY * rect_h);
+        gp_Pnt endPos3d = ElCLib::To3d(plane, endPos2d);
+        worldPosQ = QVector3D(endPos3d.X(), endPos3d.Y(), endPos3d.Z());
+    } else {
+        worldPosQ = mousePosQ;
+        if (m_viewport->isSnappingOrigin()) {
+            const auto& origin = plane.Location();
+            worldPosQ.setX(origin.X()); worldPosQ.setY(origin.Y()); worldPosQ.setZ(origin.Z());
+        } else if (m_viewport->isSnappingVertex()) {
+            worldPosQ.setX(m_viewport->snapVertex().X()); worldPosQ.setY(m_viewport->snapVertex().Y()); worldPosQ.setZ(m_viewport->snapVertex().Z());
+        }
+    }
+    gp_Pnt p3_3d(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+    gp_Pnt p2_3d, p4_3d;
+
+    gp_Pnt2d p1_2d(gp_Vec(plane.Location(), p1_3d).Dot(plane.XDirection()), gp_Vec(plane.Location(), p1_3d).Dot(plane.YDirection()));
+    gp_Pnt2d p3_2d(gp_Vec(plane.Location(), p3_3d).Dot(plane.XDirection()), gp_Vec(plane.Location(), p3_3d).Dot(plane.YDirection()));
+    gp_Pnt2d p2_2d(p3_2d.X(), p1_2d.Y());
+    p2_3d = ElCLib::To3d(plane, p2_2d);
+
+    double w = qAbs(p3_2d.X() - p1_2d.X());
+    double h = qAbs(p3_2d.Y() - p1_2d.Y());
+
+    painter.setRenderHint(QPainter::Antialiasing);
+    QFontMetrics fm(painter.font());
+
+    QVector3D p1_q(p1_3d.X(), p1_3d.Y(), p1_3d.Z());
+    QVector3D p2_q(p2_3d.X(), p2_3d.Y(), p2_3d.Z());
+    QVector3D p3_q(p3_3d.X(), p3_3d.Y(), p3_3d.Z());
+
+    // Width dimension
+    QVector3D widthTextPos3D = (p1_q + p2_q) / 2.0f;
+    QVector3D screenPosW = m_viewport->project(widthTextPos3D, modelView, projection, m_viewport->rect());
+    if (screenPosW.z() < 1.0f) {
+        QString widthText = widthFromInput ? widthInput : QString::number(w, 'f', 2);
+        QRect textRect = fm.boundingRect(widthText + "__");
+        textRect.moveCenter(screenPosW.toPoint() + QPoint(0, (p3_2d.Y() > p1_2d.Y()) ? -15 : 15));
+        if (m_viewport->property("dimensionEditMode").toString() == "width") {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+        } else {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+        }
+        painter.setPen(Qt::white);
+        painter.drawText(textRect, Qt::AlignCenter, widthText);
+    }
+
+    // Height dimension
+    QVector3D heightTextPos3D = (p2_q + p3_q) / 2.0f;
+    QVector3D screenPosH = m_viewport->project(heightTextPos3D, modelView, projection, m_viewport->rect());
+    if (screenPosH.z() < 1.0f) {
+        QString heightText = heightFromInput ? heightInput : QString::number(h, 'f', 2);
+        QRect textRect = fm.boundingRect(heightText + "__");
+        textRect.moveCenter(screenPosH.toPoint() + QPoint((p3_2d.X() > p1_2d.X()) ? 15 : -15, 0));
+        if (m_viewport->property("dimensionEditMode").toString() == "height") {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+        } else {
+            painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+        }
+        painter.setPen(Qt::white);
+        painter.drawText(textRect, Qt::AlignCenter, heightText);
+    }
+}

src/RectangleTool.h

@@ -0,0 +1,35 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef RECTANGLETOOL_H
+#define RECTANGLETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class RectangleTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit RectangleTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_firstRectanglePoint;
+};
+
+#endif // RECTANGLETOOL_H

src/SketchCircle.cpp

@@ -0,0 +1,63 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "SketchCircle.h"
+#include <QJsonArray>
+
+namespace
+{
+    void pointToJson(const gp_Pnt& p, QJsonArray& arr)
+    {
+        arr.append(p.X());
+        arr.append(p.Y());
+        arr.append(p.Z());
+    }
+
+    gp_Pnt jsonToPoint(const QJsonArray& arr)
+    {
+        return gp_Pnt(arr[0].toDouble(), arr[1].toDouble(), arr[2].toDouble());
+    }
+}
+
+SketchCircle::SketchCircle() : m_radius(0.0)
+{
+}
+
+SketchCircle::SketchCircle(const gp_Pnt& center, double radius)
+    : m_center(center), m_radius(radius)
+{
+}
+
+SketchObject::ObjectType SketchCircle::type() const
+{
+    return ObjectType::Circle;
+}
+
+void SketchCircle::read(const QJsonObject& json)
+{
+    m_center = jsonToPoint(json["center"].toArray());
+    m_radius = json["radius"].toDouble();
+}
+
+void SketchCircle::write(QJsonObject& json) const
+{
+    QJsonArray centerArr;
+    pointToJson(m_center, centerArr);
+    json["center"] = centerArr;
+    json["radius"] = m_radius;
+    json["type"] = "Circle";
+}
+
+const gp_Pnt& SketchCircle::center() const
+{
+    return m_center;
+}
+
+double SketchCircle::radius() const
+{
+    return m_radius;
+}

src/SketchCircle.h

@@ -0,0 +1,33 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef SKETCHCIRCLE_H
+#define SKETCHCIRCLE_H
+
+#include "SketchObject.h"
+#include <gp_Pnt.hxx>
+
+class SketchCircle : public SketchObject
+{
+public:
+    SketchCircle();
+    SketchCircle(const gp_Pnt& center, double radius);
+
+    ObjectType type() const override;
+
+    void read(const QJsonObject& json) override;
+    void write(QJsonObject& json) const override;
+
+    const gp_Pnt& center() const;
+    double radius() const;
+
+private:
+    gp_Pnt m_center;
+    double m_radius;
+};
+
+#endif // SKETCHCIRCLE_H

src/SketchFeature.cpp

@@ -1,12 +1,53 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "SketchFeature.h"
 #include "SketchObject.h"
 #include "SketchLine.h"
+#include "SketchRectangle.h"
+
+#include <BRep_Builder.hxx>
+#include <TopoDS_Compound.hxx>
+#include <gp_Pnt.hxx>
+#include <gp_Dir.hxx>
 
 #include <QJsonArray>
+#include <QJsonObject>
+
+namespace
+{
+    void gpPntToJson(const gp_Pnt& p, QJsonObject& json) {
+        json["x"] = p.X();
+        json["y"] = p.Y();
+        json["z"] = p.Z();
+    }
+
+    gp_Pnt jsonToGpPnt(const QJsonObject& json) {
+        return gp_Pnt(json["x"].toDouble(), json["y"].toDouble(), json["z"].toDouble());
+    }
+
+    void gpDirToJson(const gp_Dir& d, QJsonObject& json) {
+        json["x"] = d.X();
+        json["y"] = d.Y();
+        json["z"] = d.Z();
+    }
+
+    gp_Dir jsonToGpDir(const QJsonObject& json) {
+        return gp_Dir(json["x"].toDouble(), json["y"].toDouble(), json["z"].toDouble());
+    }
+}
 
 SketchFeature::SketchFeature(const QString& name)
-    : Feature(name)
+    : Feature(name), m_plane(gp_Pnt(0, 0, 0), gp::DZ())
 {
+    BRep_Builder builder;
+    TopoDS_Compound compound;
+    builder.MakeCompound(compound);
+    m_shape = compound;
 }
 
 SketchFeature::~SketchFeature()
@@ -19,12 +60,12 @@ QString SketchFeature::type() const
     return "Sketch";
 }
 
-void SketchFeature::setPlane(SketchPlane plane)
+void SketchFeature::setPlane(const gp_Ax2& plane)
 {
     m_plane = plane;
 }
 
-SketchFeature::SketchPlane SketchFeature::plane() const
+const gp_Ax2& SketchFeature::plane() const
 {
     return m_plane;
 }
@@ -34,6 +75,12 @@ const TopoDS_Shape& SketchFeature::shape() const
     return m_shape;
 }
 
+void SketchFeature::addShape(const TopoDS_Shape& shape)
+{
+    BRep_Builder builder;
+    builder.Add(m_shape, shape);
+}
+
 void SketchFeature::addObject(SketchObject* object)
 {
     m_objects.append(object);
@@ -47,11 +94,14 @@ const QList<SketchObject*>& SketchFeature::objects() const
 void SketchFeature::read(const QJsonObject& json)
 {
     Feature::read(json);
-    if (json.contains("plane") && json["plane"].isString()) {
+    if (json.contains("plane") && json["plane"].isObject()) {
-        QString planeStr = json["plane"].toString();
+        QJsonObject planeJson = json["plane"].toObject();
-        if (planeStr == "XY") m_plane = SketchPlane::XY;
+        if (planeJson.contains("origin") && planeJson.contains("normal") && planeJson.contains("x_direction")) {
-        else if (planeStr == "XZ") m_plane = SketchPlane::XZ;
+            gp_Pnt origin = jsonToGpPnt(planeJson["origin"].toObject());
-        else if (planeStr == "YZ") m_plane = SketchPlane::YZ;
+            gp_Dir normal = jsonToGpDir(planeJson["normal"].toObject());
+            gp_Dir x_dir = jsonToGpDir(planeJson["x_direction"].toObject());
+            m_plane = gp_Ax2(origin, normal, x_dir);
+        }
     }
 
     if (json.contains("objects") && json["objects"].isArray()) {
@@ -66,6 +116,10 @@ void SketchFeature::read(const QJsonObject& json)
                     auto line = new SketchLine();
                     line->read(objectJson);
                     m_objects.append(line);
+                } else if (type == "Rectangle") {
+                    auto rect = new SketchRectangle();
+                    rect->read(objectJson);
+                    m_objects.append(rect);
                 }
             }
         }
@@ -75,13 +129,22 @@ void SketchFeature::read(const QJsonObject& json)
 void SketchFeature::write(QJsonObject& json) const
 {
     Feature::write(json);
-    QString planeStr;
+
-    switch (m_plane) {
+    QJsonObject planeJson;
-        case SketchPlane::XY: planeStr = "XY"; break;
+
-        case SketchPlane::XZ: planeStr = "XZ"; break;
+    QJsonObject originJson;
-        case SketchPlane::YZ: planeStr = "YZ"; break;
+    gpPntToJson(m_plane.Location(), originJson);
-    }
+    planeJson["origin"] = originJson;
-    json["plane"] = planeStr;
+
+    QJsonObject normalJson;
+    gpDirToJson(m_plane.Direction(), normalJson);
+    planeJson["normal"] = normalJson;
+
+    QJsonObject xDirJson;
+    gpDirToJson(m_plane.XDirection(), xDirJson);
+    planeJson["x_direction"] = xDirJson;
+
+    json["plane"] = planeJson;
 
     QJsonArray objectsArray;
     for (const auto& object : m_objects) {

src/SketchFeature.h

@@ -1,7 +1,15 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef SKETCHFEATURE_H
 #define SKETCHFEATURE_H
 
 #include <TopoDS_Shape.hxx>
+#include <gp_Ax2.hxx>
 #include <QList>
 #include "Feature.h"
 
@@ -10,21 +18,16 @@ class SketchObject;
 class SketchFeature : public Feature
 {
 public:
-    enum class SketchPlane {
-        XY,
-        XZ,
-        YZ
-    };
-
     SketchFeature(const QString& name);
     ~SketchFeature();
 
     QString type() const override;
 
-    void setPlane(SketchPlane plane);
+    void setPlane(const gp_Ax2& plane);
-    SketchPlane plane() const;
+    const gp_Ax2& plane() const;
 
     const TopoDS_Shape& shape() const;
+    void addShape(const TopoDS_Shape& shape);
 
     void addObject(SketchObject* object);
     const QList<SketchObject*>& objects() const;
@@ -33,7 +36,7 @@ public:
     void write(QJsonObject &json) const override;
 
 private:
-    SketchPlane m_plane;
+    gp_Ax2 m_plane;
     TopoDS_Shape m_shape;
     QList<SketchObject*> m_objects;
 };

src/SketchGrid.cpp

@@ -1,10 +1,44 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "SketchGrid.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
 #include <QOpenGLContext>
 #include <QOpenGLExtraFunctions>
 #include <QOpenGLShaderProgram>
+#include <QPainter>
 #include <QVector>
+#include <gp_Ax2.hxx>
 
-SketchGrid::SketchGrid()
+namespace {
+struct GridParams {
+    float minorIncrement;
+    float majorIncrement;
+    int gridSize;
+};
+
+GridParams getGridParams(float distance)
+{
+    if (distance > 500.0f) {
+        return { 20.0f, 100.0f, 1000 };
+    } else if (distance > 250.0f) {
+        return { 10.0f, 50.0f, 1000 };
+    } else if (distance > 50.0f) {
+        return { 5.0f, 25.0f, 1000 };
+    } else if (distance > 10.0f) {
+        return { 1.0f, 5.0f, 100 };
+    } else { // zoomed in
+        return { 0.2f, 1.0f, 10 };
+    }
+}
+} // namespace
+
+SketchGrid::SketchGrid(ViewportWidget* viewport) : m_viewport(viewport)
 {
 }
 
@@ -29,7 +63,7 @@ void SketchGrid::initializeGL()
     m_vbo.release();
 }
 
-void SketchGrid::paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
+void SketchGrid::paintGL(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
     GLint previous_vao = 0;
     glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &previous_vao);
@@ -44,82 +78,130 @@ void SketchGrid::paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram,
     QOpenGLContext::currentContext()->extraFunctions()->glBindVertexArray(previous_vao);
 }
 
-void SketchGrid::drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
+void SketchGrid::drawGridLines(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    const int gridSize = 50;
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
-    const float darkFactor = 0.8f;
+    const float minorIncrement = params.minorIncrement;
-    QVector<GLfloat> lightLines;
+    const int gridSize = params.gridSize;
-    QVector<GLfloat> darkLines;
 
-    for (int i = -gridSize; i <= gridSize; ++i)
+    const auto& origin = plane.Location();
-    {
+    const auto& xDir = plane.XDirection();
-        if (i == 0) continue;
+    const auto& yDir = plane.YDirection();
-        QVector<GLfloat>& current_vector = (i % 5 == 0) ? darkLines : lightLines;
+    QVector3D originVec(origin.X(), origin.Y(), origin.Z());
-        if (plane == XY) {
+    QVector3D xDirVec(xDir.X(), xDir.Y(), xDir.Z());
-            current_vector << i << 0 << -gridSize << i << 0 << gridSize;
+    QVector3D yDirVec(yDir.X(), yDir.Y(), yDir.Z());
-            current_vector << -gridSize << 0 << i << gridSize << 0 << i;
+
-        } else if (plane == XZ) {
+    QVector<GLfloat> minorLines;
-            current_vector << i << -gridSize << 0 << i << gridSize << 0;
+    QVector<GLfloat> majorLines;
-            current_vector << -gridSize << i << 0 << gridSize << i << 0;
+
-        } else { // YZ
+    int numLines = gridSize / minorIncrement;
-            current_vector << 0 << i << -gridSize << 0 << i << gridSize;
+    for (int i = -numLines; i <= numLines; ++i) {
-            current_vector << 0 << -gridSize << i << 0 << gridSize << i;
+        if (i == 0)
-        }
+            continue;
+
+        float pos = i * minorIncrement;
+        QVector<GLfloat>& current_vector = (i % 5 == 0) ? majorLines : minorLines;
+
+        QVector3D p1 = originVec + pos * xDirVec - gridSize * yDirVec;
+        QVector3D p2 = originVec + pos * xDirVec + gridSize * yDirVec;
+        current_vector << p1.x() << p1.y() << p1.z() << p2.x() << p2.y() << p2.z();
+
+        QVector3D p3 = originVec - gridSize * xDirVec + pos * yDirVec;
+        QVector3D p4 = originVec + gridSize * xDirVec + pos * yDirVec;
+        current_vector << p3.x() << p3.y() << p3.z() << p4.x() << p4.y() << p4.z();
     }
 
     m_vbo.bind();
 
-    // Draw lighter lines
+    // Draw minor lines
-    shaderProgram->setUniformValue(colorLoc, QVector4D(0.5f, 0.5f, 0.5f, 1.0f));
+    shaderProgram->setUniformValue(colorLoc, QVector4D(0.4f, 0.4f, 0.4f, 1.0f));
     glLineWidth(1.0f);
-    m_vbo.allocate(lightLines.constData(), lightLines.size() * sizeof(GLfloat));
+    m_vbo.allocate(minorLines.constData(), minorLines.size() * sizeof(GLfloat));
-    glDrawArrays(GL_LINES, 0, lightLines.size() / 3);
+    glDrawArrays(GL_LINES, 0, minorLines.size() / 3);
 
-    // Draw darker lines
+    // Draw major lines
-    shaderProgram->setUniformValue(colorLoc, QVector4D(0.5f * darkFactor, 0.5f * darkFactor, 0.5f * darkFactor, 1.0f));
+    shaderProgram->setUniformValue(colorLoc, QVector4D(0.6f, 0.6f, 0.6f, 1.0f));
-    glLineWidth(1.5f);
+    glLineWidth(1.0f);
-    m_vbo.allocate(darkLines.constData(), darkLines.size() * sizeof(GLfloat));
+    m_vbo.allocate(majorLines.constData(), majorLines.size() * sizeof(GLfloat));
-    glDrawArrays(GL_LINES, 0, darkLines.size() / 3);
+    glDrawArrays(GL_LINES, 0, majorLines.size() / 3);
 }
 
-void SketchGrid::drawAxes(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
+void SketchGrid::drawAxes(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    const int axisLength = 50;
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
+    const int axisLength = params.gridSize;
+
+    const auto& origin = plane.Location();
+    const auto& xDir = plane.XDirection();
+    const auto& yDir = plane.YDirection();
+    QVector3D originVec(origin.X(), origin.Y(), origin.Z());
+    QVector3D xDirVec(xDir.X(), xDir.Y(), xDir.Z());
+    QVector3D yDirVec(yDir.X(), yDir.Y(), yDir.Z());
+
     QVector<GLfloat> vertices;
 
     glLineWidth(2.0f);
     m_vbo.bind();
 
     // X Axis (Red)
-    if (plane == XY || plane == XZ) {
     vertices.clear();
-        vertices << -axisLength << 0 << 0 << axisLength << 0 << 0;
+    QVector3D p1 = originVec - axisLength * xDirVec;
+    QVector3D p2 = originVec + axisLength * xDirVec;
+    vertices << p1.x() << p1.y() << p1.z() << p2.x() << p2.y() << p2.z();
     shaderProgram->setUniformValue(colorLoc, QVector4D(1.0f, 0.0f, 0.0f, 1.0f));
     m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
     glDrawArrays(GL_LINES, 0, 2);
-    }
+
     // Y Axis (Green)
-    if (plane == XY || plane == YZ) {
     vertices.clear();
-        vertices << 0 << 0 << -axisLength << 0 << 0 << axisLength;
+    QVector3D p3 = originVec - axisLength * yDirVec;
+    QVector3D p4 = originVec + axisLength * yDirVec;
+    vertices << p3.x() << p3.y() << p3.z() << p4.x() << p4.y() << p4.z();
     shaderProgram->setUniformValue(colorLoc, QVector4D(0.0f, 1.0f, 0.0f, 1.0f));
     m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
     glDrawArrays(GL_LINES, 0, 2);
-    }
-    // Z Axis (Blue)
-    if (plane == XZ || plane == YZ) {
-        vertices.clear();
-        vertices << 0 << -axisLength << 0 << 0 << axisLength << 0;
-        shaderProgram->setUniformValue(colorLoc, QVector4D(0.0f, 0.0f, 1.0f, 1.0f));
-        m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
-        glDrawArrays(GL_LINES, 0, 2);
-    }
 
     // Origin dot
     glPointSize(5.0f);
     vertices.clear();
-    vertices << 0.0f << 0.0f << 0.0f;
+    vertices << originVec.x() << originVec.y() << originVec.z();
     shaderProgram->setUniformValue(colorLoc, QVector4D(1.0f, 1.0f, 1.0f, 1.0f)); // White
     m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
     glDrawArrays(GL_POINTS, 0, 1);
 }
+
+void SketchGrid::paintAxisLabels(QPainter& painter, const gp_Ax2& plane, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    painter.setPen(Qt::white);
+    painter.setFont(QFont("Arial", 10));
+
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
+    const float majorIncrement = params.majorIncrement;
+    const int range = params.gridSize;
+
+    const auto& origin = plane.Location();
+    const auto& xDir = plane.XDirection();
+    const auto& yDir = plane.YDirection();
+    QVector3D originVec(origin.X(), origin.Y(), origin.Z());
+    QVector3D xDirVec(xDir.X(), xDir.Y(), xDir.Z());
+    QVector3D yDirVec(yDir.X(), yDir.Y(), yDir.Z());
+
+    auto drawLabelsForAxis = [&](const QVector3D& axisDir) {
+        int numLabels = range / majorIncrement;
+        for (int i = -numLabels; i <= numLabels; ++i) {
+            if (i == 0)
+                continue;
+
+            float val = i * majorIncrement;
+            QVector3D worldCoord = originVec + val * axisDir;
+
+            QVector3D screenPos = m_viewport->project(worldCoord, modelView, projection, m_viewport->rect());
+            if (screenPos.z() < 1.0f) { // Not clipped
+                painter.drawText(screenPos.toPoint(), QString::number(val));
+            }
+        }
+    };
+
+    drawLabelsForAxis(xDirVec);
+    drawLabelsForAxis(yDirVec);
+}

src/SketchGrid.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef SKETCHGRID_H
 #define SKETCHGRID_H
 
@@ -5,30 +12,29 @@
 #include <QMatrix4x4>
 #include <QOpenGLVertexArrayObject>
 #include <QOpenGLBuffer>
+#include <gp_Ax2.hxx>
 
 class QOpenGLShaderProgram;
+class QPainter;
+class ViewportWidget;
 
 class SketchGrid : protected QOpenGLFunctions
 {
 public:
-    enum SketchPlane {
+    explicit SketchGrid(ViewportWidget* viewport);
-        XY = 1,
-        XZ = 2,
-        YZ = 3
-    };
-
-    SketchGrid();
     ~SketchGrid();
 
     void initializeGL();
-    void paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
+    void paintGL(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
+    void paintAxisLabels(QPainter& painter, const gp_Ax2& plane, const QMatrix4x4& modelView, const QMatrix4x4& projection);
 
 private:
-    void drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
+    void drawGridLines(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
-    void drawAxes(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
+    void drawAxes(const gp_Ax2& plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
 
     QOpenGLVertexArrayObject m_vao;
     QOpenGLBuffer m_vbo;
+    ViewportWidget* m_viewport = nullptr;
 };
 
 #endif // SKETCHGRID_H

src/SketchLine.cpp

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "SketchLine.h"
 #include <QJsonObject>
 

src/SketchLine.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef SKETCHLINE_H
 #define SKETCHLINE_H
 

src/SketchObject.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef SKETCHOBJECT_H
 #define SKETCHOBJECT_H
 
@@ -7,7 +14,9 @@ class SketchObject
 {
 public:
     enum class ObjectType {
-        Line
+        Line,
+        Rectangle,
+        Circle
     };
 
     SketchObject() = default;

src/SketchRectangle.cpp

@@ -0,0 +1,68 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "SketchRectangle.h"
+#include <QJsonArray>
+
+namespace
+{
+    void pointToJson(const gp_Pnt& p, QJsonArray& arr)
+    {
+        arr.append(p.X());
+        arr.append(p.Y());
+        arr.append(p.Z());
+    }
+
+    gp_Pnt jsonToPoint(const QJsonArray& arr)
+    {
+        return gp_Pnt(arr[0].toDouble(), arr[1].toDouble(), arr[2].toDouble());
+    }
+}
+
+SketchRectangle::SketchRectangle()
+{
+}
+
+SketchRectangle::SketchRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2)
+    : m_corner1(corner1), m_corner2(corner2)
+{
+}
+
+SketchObject::ObjectType SketchRectangle::type() const
+{
+    return ObjectType::Rectangle;
+}
+
+void SketchRectangle::read(const QJsonObject& json)
+{
+    if (json.contains("corner1") && json["corner1"].isArray()) {
+        m_corner1 = jsonToPoint(json["corner1"].toArray());
+    }
+    if (json.contains("corner2") && json["corner2"].isArray()) {
+        m_corner2 = jsonToPoint(json["corner2"].toArray());
+    }
+}
+
+void SketchRectangle::write(QJsonObject& json) const
+{
+    json["type"] = "Rectangle";
+    QJsonArray c1, c2;
+    pointToJson(m_corner1, c1);
+    pointToJson(m_corner2, c2);
+    json["corner1"] = c1;
+    json["corner2"] = c2;
+}
+
+const gp_Pnt& SketchRectangle::corner1() const
+{
+    return m_corner1;
+}
+
+const gp_Pnt& SketchRectangle::corner2() const
+{
+    return m_corner2;
+}

src/SketchRectangle.h

@@ -0,0 +1,33 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef SKETCHRECTANGLE_H
+#define SKETCHRECTANGLE_H
+
+#include "SketchObject.h"
+#include <gp_Pnt.hxx>
+
+class SketchRectangle : public SketchObject
+{
+public:
+    SketchRectangle();
+    SketchRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2);
+
+    ObjectType type() const override;
+
+    void read(const QJsonObject& json) override;
+    void write(QJsonObject& json) const override;
+
+    const gp_Pnt& corner1() const;
+    const gp_Pnt& corner2() const;
+
+private:
+    gp_Pnt m_corner1;
+    gp_Pnt m_corner2;
+};
+
+#endif // SKETCHRECTANGLE_H

src/SketchTool.cpp

@@ -0,0 +1,86 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "SketchTool.h"
+#include "ViewportWidget.h"
+#include <QKeyEvent>
+
+SketchTool::SketchTool(ViewportWidget* viewport)
+    : QObject(viewport), m_viewport(viewport)
+{
+}
+
+void SketchTool::activate()
+{
+    m_isDefining = false;
+}
+
+void SketchTool::deactivate()
+{
+    m_isDefining = false;
+    for (const QString& propName : m_dimensionPropertyNames.values()) {
+        m_viewport->setProperty(propName.toUtf8().constData(), "");
+    }
+    m_dimensionModes.clear();
+    m_dimensionPropertyNames.clear();
+}
+
+void SketchTool::keyPressEvent(QKeyEvent *event)
+{
+    if (m_isDefining) {
+        if (event->key() == Qt::Key_Tab) {
+            if (m_dimensionModes.size() > 1) {
+                QString currentMode = m_viewport->property("dimensionEditMode").toString();
+                int currentIndex = m_dimensionModes.indexOf(currentMode);
+                if (currentIndex != -1) {
+                    int nextIndex = (currentIndex + 1) % m_dimensionModes.size();
+                    m_viewport->setProperty("dimensionEditMode", m_dimensionModes[nextIndex]);
+                    m_viewport->update();
+                }
+            }
+            return;
+        }
+
+        QString editMode = m_viewport->property("dimensionEditMode").toString();
+        if (m_dimensionPropertyNames.contains(editMode)) {
+            QString propertyName = m_dimensionPropertyNames[editMode];
+            QString currentInput = m_viewport->property(propertyName.toUtf8().constData()).toString();
+
+            if (event->key() >= Qt::Key_0 && event->key() <= Qt::Key_9) {
+                currentInput += event->text();
+                m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                m_viewport->update();
+                return;
+            } else if (event->key() == Qt::Key_Period) {
+                if (!currentInput.contains('.')) {
+                    currentInput += '.';
+                    m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                    m_viewport->update();
+                }
+                return;
+            } else if (event->key() == Qt::Key_Backspace) {
+                if (!currentInput.isEmpty()) {
+                    currentInput.chop(1);
+                    m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                    m_viewport->update();
+                }
+                return;
+            }
+        }
+
+        if (event->key() == Qt::Key_Return || event->key() == Qt::Key_Enter) {
+            finalizeCreation();
+            m_viewport->update();
+            return;
+        } else if (event->key() == Qt::Key_Escape) {
+            deactivate();
+            m_viewport->deactivateActiveTool();
+            m_viewport->update();
+            return;
+        }
+    }
+}

src/SketchTool.h

@@ -0,0 +1,47 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef SKETCHTOOL_H
+#define SKETCHTOOL_H
+
+#include <QObject>
+#include <QStringList>
+#include <QMap>
+
+class QMouseEvent;
+class QKeyEvent;
+class ViewportWidget;
+class QOpenGLShaderProgram;
+class QPainter;
+class QMatrix4x4;
+
+class SketchTool : public QObject
+{
+    Q_OBJECT
+public:
+    explicit SketchTool(ViewportWidget* viewport);
+    virtual ~SketchTool() = default;
+
+    virtual void mousePressEvent(QMouseEvent *event) = 0;
+    virtual void mouseMoveEvent(QMouseEvent *event) = 0;
+    virtual void keyPressEvent(QKeyEvent *event);
+
+    virtual void paintGL() = 0;
+    virtual void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) = 0;
+
+    virtual void activate();
+    virtual void deactivate();
+
+protected:
+    virtual void finalizeCreation() = 0;
+    ViewportWidget* m_viewport;
+    bool m_isDefining = false;
+    QStringList m_dimensionModes;
+    QMap<QString, QString> m_dimensionPropertyNames;
+};
+
+#endif // SKETCHTOOL_H

src/Snapping.cpp

@@ -0,0 +1,164 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#include "Snapping.h"
+
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include "Document.h"
+#include "SketchFeature.h"
+#include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchObject.h"
+#include "ApplicationController.h"
+
+#include <QOpenGLShaderProgram>
+#include <QVector>
+#include <QtMath>
+#include <optional>
+#include <gp_Ax2.hxx>
+#include <gp_Pnt2d.hxx>
+#include <gp_Vec.hxx>
+#include <ElCLib.hxx>
+
+Snapping::Snapping(ViewportWidget* viewport) : m_viewport(viewport)
+{
+}
+
+bool Snapping::update(const QPoint& mousePos)
+{
+    bool oldIsSnappingOrigin = m_isSnappingOrigin;
+    bool oldIsSnappingVertex = m_isSnappingVertex;
+
+    bool shouldSnap = false;
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (currentPlaneOpt && m_viewport->activeTool() != static_cast<int>(ApplicationController::ToolType::None)) {
+        const auto& plane = currentPlaneOpt.value();
+        QVector3D worldPosQ = m_viewport->unproject(mousePos, plane);
+        gp_Pnt worldPos(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+        const float snapRectHalfSize = 0.0075f * -m_viewport->camera()->zoom();
+
+        gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPos).Dot(plane.YDirection()));
+        shouldSnap = qAbs(worldPos2d.X()) < snapRectHalfSize && qAbs(worldPos2d.Y()) < snapRectHalfSize;
+    }
+
+    m_isSnappingOrigin = shouldSnap;
+    if (m_isSnappingOrigin) {
+        m_isSnappingVertex = false;
+    }
+
+    m_isSnappingVertex = false;
+    if (!m_isSnappingOrigin && m_viewport->document() && currentPlaneOpt && m_viewport->activeTool() != static_cast<int>(ApplicationController::ToolType::None)) {
+        const auto& plane = currentPlaneOpt.value();
+        QVector3D worldPosQ = m_viewport->unproject(mousePos, plane);
+        gp_Pnt worldPos(worldPosQ.x(), worldPosQ.y(), worldPosQ.z());
+        gp_Pnt2d worldPos2d(gp_Vec(plane.Location(), worldPos).Dot(plane.XDirection()), gp_Vec(plane.Location(), worldPos).Dot(plane.YDirection()));
+        const float snapRectHalfSize = 0.0075f * -m_viewport->camera()->zoom();
+
+        for (Feature* feature : m_viewport->document()->features()) {
+            if (auto sketch = dynamic_cast<SketchFeature*>(feature)) {
+                for (const auto& obj : sketch->objects()) {
+                    if (obj->type() == SketchObject::ObjectType::Line) {
+                        auto line = static_cast<const SketchLine*>(obj);
+                        const gp_Pnt vertices[] = {line->startPoint(), line->endPoint()};
+                        for (const auto& vertex : vertices) {
+                            gp_Pnt2d vertex2d(gp_Vec(plane.Location(), vertex).Dot(plane.XDirection()), gp_Vec(plane.Location(), vertex).Dot(plane.YDirection()));
+                            bool isClose = qAbs(worldPos2d.X() - vertex2d.X()) < snapRectHalfSize && qAbs(worldPos2d.Y() - vertex2d.Y()) < snapRectHalfSize;
+
+                            if (isClose) {
+                                m_isSnappingVertex = true;
+                                m_snapVertex = vertex;
+                                goto end_snap_check;
+                            }
+                        }
+                    } else if (obj->type() == SketchObject::ObjectType::Rectangle) {
+                        auto rect = static_cast<const SketchRectangle*>(obj);
+                        const auto& rectPlane = sketch->plane();
+                        const auto& p1 = rect->corner1();
+                        const auto& p3 = rect->corner2();
+
+                        gp_Pnt2d p1_2d(gp_Vec(rectPlane.Location(), p1).Dot(rectPlane.XDirection()), gp_Vec(rectPlane.Location(), p1).Dot(rectPlane.YDirection()));
+                        gp_Pnt2d p3_2d(gp_Vec(rectPlane.Location(), p3).Dot(rectPlane.XDirection()), gp_Vec(rectPlane.Location(), p3).Dot(rectPlane.YDirection()));
+
+                        gp_Pnt2d p2_2d(p3_2d.X(), p1_2d.Y());
+                        gp_Pnt2d p4_2d(p1_2d.X(), p3_2d.Y());
+
+                        gp_Pnt p2 = ElCLib::To3d(rectPlane, p2_2d);
+                        gp_Pnt p4 = ElCLib::To3d(rectPlane, p4_2d);
+
+                        const gp_Pnt vertices[] = {p1, p2, p3, p4};
+                        for (const auto& vertex : vertices) {
+                            gp_Pnt2d vertex2d(gp_Vec(plane.Location(), vertex).Dot(plane.XDirection()), gp_Vec(plane.Location(), vertex).Dot(plane.YDirection()));
+                            bool isClose = qAbs(worldPos2d.X() - vertex2d.X()) < snapRectHalfSize && qAbs(worldPos2d.Y() - vertex2d.Y()) < snapRectHalfSize;
+
+                            if (isClose) {
+                                m_isSnappingVertex = true;
+                                m_snapVertex = vertex;
+                                goto end_snap_check;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    end_snap_check:;
+    }
+
+    return (oldIsSnappingOrigin != m_isSnappingOrigin) || (oldIsSnappingVertex != m_isSnappingVertex);
+}
+
+void Snapping::paintGL() const
+{
+    if (!m_isSnappingOrigin && !m_isSnappingVertex) {
+        return;
+    }
+
+    QVector<GLfloat> vertices;
+    auto currentPlaneOpt = m_viewport->currentPlane();
+    if (!currentPlaneOpt) {
+        return;
+    }
+    const auto& plane = currentPlaneOpt.value();
+    const auto& xDir = plane.XDirection();
+    const auto& yDir = plane.YDirection();
+    QVector3D X(xDir.X(), xDir.Y(), xDir.Z());
+    QVector3D Y(yDir.X(), yDir.Y(), yDir.Z());
+    const float rectSize = 0.0075f * -m_viewport->camera()->zoom();
+
+    if (m_isSnappingOrigin) {
+        const auto& o = plane.Location();
+        QVector3D O(o.X(), o.Y(), o.Z());
+
+        QVector3D p1 = O - rectSize * X - rectSize * Y;
+        QVector3D p2 = O + rectSize * X - rectSize * Y;
+        QVector3D p3 = O + rectSize * X + rectSize * Y;
+        QVector3D p4 = O - rectSize * X + rectSize * Y;
+        vertices << p1.x() << p1.y() << p1.z() << p2.x() << p2.y() << p2.z();
+        vertices << p2.x() << p2.y() << p2.z() << p3.x() << p3.y() << p3.z();
+        vertices << p3.x() << p3.y() << p3.z() << p4.x() << p4.y() << p4.z();
+        vertices << p4.x() << p4.y() << p4.z() << p1.x() << p1.y() << p1.z();
+    } else if (m_isSnappingVertex) {
+        const auto& v = m_snapVertex;
+        QVector3D V(v.X(), v.Y(), v.Z());
+
+        QVector3D p1 = V - rectSize * X - rectSize * Y;
+        QVector3D p2 = V + rectSize * X - rectSize * Y;
+        QVector3D p3 = V + rectSize * X + rectSize * Y;
+        QVector3D p4 = V - rectSize * X + rectSize * Y;
+        vertices << p1.x() << p1.y() << p1.z() << p2.x() << p2.y() << p2.z();
+        vertices << p2.x() << p2.y() << p2.z() << p3.x() << p3.y() << p3.z();
+        vertices << p3.x() << p3.y() << p3.z() << p4.x() << p4.y() << p4.z();
+        vertices << p4.x() << p4.y() << p4.z() << p1.x() << p1.y() << p1.z();
+    }
+    m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 0.5f));
+    m_viewport->vbo().bind();
+    m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glDrawArrays(GL_LINES, 0, vertices.size() / 3);
+    glDisable(GL_BLEND);
+}

src/Snapping.h

@@ -0,0 +1,35 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
+#ifndef SNAPPING_H
+#define SNAPPING_H
+
+#include <gp_Pnt.hxx>
+#include <QPoint>
+
+class ViewportWidget;
+
+class Snapping
+{
+public:
+    explicit Snapping(ViewportWidget* viewport);
+
+    bool update(const QPoint& mousePos);
+    void paintGL() const;
+
+    bool isSnappingOrigin() const { return m_isSnappingOrigin; }
+    bool isSnappingVertex() const { return m_isSnappingVertex; }
+    const gp_Pnt& snapVertex() const { return m_snapVertex; }
+
+private:
+    ViewportWidget* m_viewport = nullptr;
+    bool m_isSnappingOrigin = false;
+    bool m_isSnappingVertex = false;
+    gp_Pnt m_snapVertex;
+};
+
+#endif // SNAPPING_H

src/ViewCube.cpp

@@ -1,12 +1,38 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include "ViewCube.h"
+#include <QGuiApplication>
 #include <QPainter>
 #include <QFont>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLTexture>
+#include <QScreen>
+#include <QSvgRenderer>
 #include <QVector>
+#include <QVector3D>
+
+namespace
+{
+QRect getHomeButtonRect(int widgetWidth) {
+    const int viewCubeSize = 150; // logical pixels
+    const int buttonSize = 24;
+    const int buttonOffsetX = 16;
+    const int buttonOffsetY = 16;
+
+    const int viewCubeX = widgetWidth - viewCubeSize;
+
+    return QRect(viewCubeX + buttonOffsetX, buttonOffsetY, buttonSize, buttonSize);
+}
+}
 
 ViewCube::ViewCube()
 {
+    m_homeButtonRenderer = new QSvgRenderer(QString(":/icons/home.svg"));
     for (int i = 0; i < 6; ++i) {
         m_faceTextures[i] = nullptr;
     }
@@ -18,6 +44,7 @@ ViewCube::~ViewCube()
         delete m_faceTextures[i];
     }
     delete m_textureShaderProgram;
+    delete m_homeButtonRenderer;
     m_cubeVbo.destroy();
     m_cubeVao.destroy();
     m_axesVbo.destroy();
@@ -32,17 +59,59 @@ void ViewCube::initializeGL()
     setupBuffers();
 }
 
-void ViewCube::paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height)
+void ViewCube::paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height, const QPoint& mousePos)
 {
-    int viewCubeSize = 150;
+    int viewCubeSize = 150 * QGuiApplication::primaryScreen()->devicePixelRatio();
     glViewport(width - viewCubeSize, height - viewCubeSize, viewCubeSize, viewCubeSize);
+
+    QRect viewCubeRect(width - viewCubeSize, 0, viewCubeSize, viewCubeSize);
+    QPoint physicalMousePos = mousePos * QGuiApplication::primaryScreen()->devicePixelRatio();
+
+    m_isHovered = viewCubeRect.contains(physicalMousePos);
+
+    float opacity = m_isHovered ? 1.0f : 0.5f;
+
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
     glClear(GL_DEPTH_BUFFER_BIT);
 
     QMatrix4x4 viewCubeProjection;
     viewCubeProjection.ortho(-2, 2, -2, 2, -10, 10);
 
-    drawViewCube(viewCubeProjection, viewMatrix);
+    drawViewCube(viewCubeProjection, viewMatrix, opacity);
     drawAxes(simpleShader, simpleShaderColorLoc, viewCubeProjection, viewMatrix);
+
+    QMatrix4x4 mvp = viewCubeProjection * viewMatrix;
+    const float axisLen = 1.7f;
+
+    QVector3D xAxisEnd(axisLen, 0.0f, 0.0f);
+    QVector3D yAxisEnd(0.0f, 0.0f, axisLen);
+    QVector3D zAxisEnd(0.0f, axisLen, 0.0f);
+
+    QVector3D xAxisNdc = mvp.map(xAxisEnd);
+    QVector3D yAxisNdc = mvp.map(yAxisEnd);
+    QVector3D zAxisNdc = mvp.map(zAxisEnd);
+
+    const int vpX = width - viewCubeSize;
+    const int vpY = 0;
+    const int vpW = viewCubeSize;
+    const int vpH = viewCubeSize;
+    const float dpr = QGuiApplication::primaryScreen()->devicePixelRatio();
+
+    m_xAxisLabelPos.setX( (xAxisNdc.x() + 1.0f) * vpW / 2.0f + vpX );
+    m_xAxisLabelPos.setY( (1.0f - xAxisNdc.y()) * vpH / 2.0f + vpY );
+    m_xAxisLabelPos /= dpr;
+
+    m_yAxisLabelPos.setX( (yAxisNdc.x() + 1.0f) * vpW / 2.0f + vpX );
+    m_yAxisLabelPos.setY( (1.0f - yAxisNdc.y()) * vpH / 2.0f + vpY );
+    m_yAxisLabelPos /= dpr;
+
+    m_zAxisLabelPos.setX( (zAxisNdc.x() + 1.0f) * vpW / 2.0f + vpX );
+    m_zAxisLabelPos.setY( (1.0f - zAxisNdc.y()) * vpH / 2.0f + vpY );
+    m_zAxisLabelPos /= dpr;
+
+    glDisable(GL_BLEND);
 }
 
 void ViewCube::createFaceTextures()
@@ -144,7 +213,7 @@ void ViewCube::setupBuffers()
     m_axesVbo.release();
 }
 
-void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view)
+void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view, float opacity)
 {
     if (!m_textureShaderProgram || !m_textureShaderProgram->isLinked()) return;
 
@@ -153,6 +222,7 @@ void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view
     m_textureShaderProgram->setUniformValue("projectionMatrix", projection);
     m_textureShaderProgram->setUniformValue("modelViewMatrix", view);
     m_textureShaderProgram->setUniformValue("texture_diffuse1", 0);
+    m_textureShaderProgram->setUniformValue("opacity", opacity);
 
     QOpenGLVertexArrayObject::Binder vaoBinder(&m_cubeVao);
     for (int i = 0; i < 6; ++i) {
@@ -193,3 +263,44 @@ void ViewCube::drawAxes(QOpenGLShaderProgram* simpleShader, int colorLoc, const
 
     glLineWidth(1.0f);
 }
+
+void ViewCube::paint2D(QPainter& painter, int widgetWidth, int widgetHeight)
+{
+    QFont font("Arial", 10, QFont::Bold);
+    painter.setFont(font);
+    painter.setPen(Qt::white);
+    QFontMetrics fm(font);
+
+    QRect xRect = fm.boundingRect("X");
+    xRect.moveCenter(m_xAxisLabelPos);
+    painter.drawText(xRect, Qt::AlignCenter, "X");
+
+    QRect yRect = fm.boundingRect("Y");
+    yRect.moveCenter(m_yAxisLabelPos);
+    painter.drawText(yRect, Qt::AlignCenter, "Y");
+
+    QRect zRect = fm.boundingRect("Z");
+    zRect.moveCenter(m_zAxisLabelPos);
+    painter.drawText(zRect, Qt::AlignCenter, "Z");
+
+    if (!m_isHovered) {
+        return;
+    }
+
+    m_homeButtonRect = getHomeButtonRect(widgetWidth);
+
+    if (m_homeButtonRenderer && m_homeButtonRenderer->isValid()) {
+        m_homeButtonRenderer->render(&painter, m_homeButtonRect);
+    }
+}
+
+bool ViewCube::handleMousePress(const QPoint& pos, int widgetWidth, int widgetHeight)
+{
+    if (!m_isHovered) {
+        return false;
+    }
+
+    QRect homeButtonRect = getHomeButtonRect(widgetWidth);
+
+    return homeButtonRect.contains(pos);
+}

src/ViewCube.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef VIEWCUBE_H
 #define VIEWCUBE_H
 
@@ -5,9 +12,12 @@
 #include <QMatrix4x4>
 #include <QOpenGLVertexArrayObject>
 #include <QOpenGLBuffer>
+#include <QPoint>
 
 class QOpenGLShaderProgram;
 class QOpenGLTexture;
+class QPainter;
+class QSvgRenderer;
 
 class ViewCube : protected QOpenGLFunctions
 {
@@ -16,15 +26,25 @@ public:
     ~ViewCube();
 
     void initializeGL();
-    void paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height);
+    void paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height, const QPoint& mousePos);
+    void paint2D(QPainter& painter, int widgetWidth, int widgetHeight);
+    bool handleMousePress(const QPoint& pos, int widgetWidth, int widgetHeight);
 
 private:
     void createFaceTextures();
     void initShaders();
     void setupBuffers();
-    void drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view);
+    void drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view, float opacity);
     void drawAxes(QOpenGLShaderProgram* simpleShader, int colorLoc, const QMatrix4x4& projection, const QMatrix4x4& view);
 
+    bool m_isHovered = false;
+    QRect m_homeButtonRect;
+    QSvgRenderer* m_homeButtonRenderer = nullptr;
+
+    QPoint m_xAxisLabelPos;
+    QPoint m_yAxisLabelPos;
+    QPoint m_zAxisLabelPos;
+
     QOpenGLTexture* m_faceTextures[6];
 
     QOpenGLShaderProgram* m_textureShaderProgram = nullptr;

src/ViewportWidget.h

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #ifndef VIEWPORTWIDGET_H
 #define VIEWPORTWIDGET_H
 
@@ -8,6 +15,8 @@
 #include <QVector3D>
 #include <QRect>
 #include <gp_Pnt.hxx>
+#include <gp_Ax2.hxx>
+#include <optional>
 #include <QMap>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLVertexArrayObject>
@@ -20,53 +29,73 @@ class Document;
 class FeatureBrowser;
 class SketchFeature;
 class Camera;
+class SketchTool;
+class Snapping;
 
 class ViewportWidget : public QOpenGLWidget, protected QOpenGLFunctions
 {
     Q_OBJECT
 
 public:
-    enum class SketchPlane {
-        NONE,
-        XY,
-        XZ,
-        YZ
-    };
-
     explicit ViewportWidget(QWidget *parent = nullptr);
     ~ViewportWidget();
 
     void setDocument(Document* document);
 
+    QVector3D project(const QVector3D& worldCoord, const QMatrix4x4& modelView, const QMatrix4x4& projection, const QRect& viewport);
+    QVector3D unproject(const QPoint& screenPos, const gp_Ax2& plane);
+    QOpenGLShaderProgram* shaderProgram() { return m_shaderProgram; }
+    QOpenGLBuffer& vbo() { return m_vbo; }
+    int colorLoc() const { return m_colorLoc; }
+    Camera* camera() const { return m_camera; }
+    Document* document() const { return m_document; }
+    std::optional<gp_Ax2> currentPlane() const { return m_currentPlane; }
+    const QPoint& currentMousePos() const { return m_currentMousePos; }
+    bool isSnappingOrigin() const;
+    bool isSnappingVertex() const;
+    const gp_Pnt& snapVertex() const;
+    int activeTool() const { return m_activeTool; }
+    bool isSnappingHorizontal() const { return m_isSnappingHorizontal; }
+    bool isSnappingVertical() const { return m_isSnappingVertical; }
+    void setSnappingHorizontal(bool snapping);
+    void setSnappingVertical(bool snapping);
+
+    void addLine(const gp_Pnt& start, const gp_Pnt& end);
+    void deactivateActiveTool();
+
 public slots:
-    void onSketchModeStarted(SketchPlane plane);
+    void onSketchModeStarted(const gp_Ax2& plane);
     void onSketchModeEnded();
     void onPlaneSelectionModeStarted();
     void onActiveToolChanged(int tool);
 
 signals:
     void lineAdded(const gp_Pnt& start, const gp_Pnt& end);
-    void planeSelected(SketchPlane plane);
+    void rectangleAdded(const gp_Pnt& corner1, const gp_Pnt& corner2);
+    void circleAdded(const gp_Pnt& center, double radius);
+    void planeSelected(const gp_Ax2& plane);
     void toolDeactivated();
 
+private slots:
+    void onRestoreStateAnimationFinished();
+
 protected:
     void initializeGL() override;
     void paintGL() override;
     void resizeGL(int w, int h) override;
 
     void mousePressEvent(QMouseEvent *event) override;
+    void mouseReleaseEvent(QMouseEvent *event) override;
     void mouseMoveEvent(QMouseEvent *event) override;
     void wheelEvent(QWheelEvent *event) override;
     void keyPressEvent(QKeyEvent *event) override;
+    bool focusNextPrevChild(bool next) override;
 
 private:
     void initShaders();
-    QVector3D project(const QVector3D& worldCoord, const QMatrix4x4& modelView, const QMatrix4x4& projection, const QRect& viewport);
-    QVector3D unproject(const QPoint& screenPos, SketchPlane plane);
-    void drawAxisLabels(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection);
     void drawSketch(const SketchFeature* sketch);
     void drawSelectionPlanes();
-    ViewportWidget::SketchPlane checkPlaneSelection(const QPoint& screenPos);
+    std::optional<gp_Ax2> checkPlaneSelection(const QPoint& screenPos);
 
     QMatrix4x4 projection;
     QOpenGLShaderProgram* m_shaderProgram = nullptr;
@@ -82,25 +111,21 @@ private:
     SketchGrid* m_sketchGrid = nullptr;
     FeatureBrowser* m_featureBrowser = nullptr;
     Document* m_document = nullptr;
-    SketchPlane m_currentPlane = SketchPlane::NONE;
+    std::optional<gp_Ax2> m_currentPlane;
 
     bool m_isSelectingPlane = false;
-    SketchPlane m_highlightedPlane = SketchPlane::NONE;
+    std::optional<gp_Ax2> m_highlightedPlane;
 
     int m_activeTool = 0;
-    bool m_isDefiningLine = false;
+    SketchTool* m_activeSketchTool = nullptr;
-    gp_Pnt m_firstLinePoint;
+    QMap<int, SketchTool*> m_sketchTools;
     QPoint m_currentMousePos;
-    bool m_isSnappingOrigin = false;
+    Snapping* m_snapping = nullptr;
-    bool m_isSnappingVertex = false;
-    gp_Pnt m_snapVertex;
     bool m_isSnappingHorizontal = false;
     bool m_isSnappingVertical = false;
 
     QMap<int, QSvgRenderer*> m_toolIcons;
     QSvgRenderer* m_cursorRenderer = nullptr;
-
-    QPoint lastPos;
 };
 
 #endif // VIEWPORTWIDGET_H

src/main.cpp

@@ -1,3 +1,10 @@
+// Unnamed CAD Software
+//
+// License: GPLv3 (or later)
+// Language: C++17
+// Notes:
+//     - use a right-handed, Z-up coordinate system to match Open CASCADE
+
 #include <QApplication>
 #include "MainWindow.h"
 #include "ApplicationController.h"

src/shaders/texture.frag

@@ -5,8 +5,10 @@ out vec4 FragColor;
 in vec2 TexCoord;
 
 uniform sampler2D texture_diffuse1;
+uniform float opacity;
 
 void main()
 {
-    FragColor = texture(texture_diffuse1, TexCoord);
+    vec4 texColor = texture(texture_diffuse1, TexCoord);
+    FragColor = vec4(texColor.rgb, texColor.a * opacity);
 }