Feature/add chamfer fillet #62572

lbartoletti · 2025-07-10T12:24:47Z

Description

This PR introduces core functionality for chamfer and fillet operations on geometric objects, commonly used in CAD applications for corner modification.

There are two implementation level:

Low-level 2D operations (QgsGeometryUtilsBase):

createChamfer() - Creates chamfer between two segments (x/y coordinates) with specified distances
createFillet() - Creates circular fillet between two segments (x/y coordinates) with specified radius

High-level geometry operations (QgsGeometry):

Vertex-based methods: chamfer(vertexIndex, ...) and fillet(vertexIndex, ...)
Segment-based methods: chamfer(seg1, seg2, ...) and fillet(seg1, seg2, ...)
Full Z/M coordinate interpolation support
Handles LineString and CompoundCurve

The algorithms support both touching and non-touching segments.

Some visual examples:

Original:

Symetric chamfer:

Asymetric Chamfer:

Fillet (preserving arc here):

Future Work

The map tools will be added in a separate PR
Maybe a processing too

Funded by: Frankurt.

…tilsBase Add createChamfer() and createFillet() methods for 2D geometric operations. These low-level functions handle segment intersection, angle calculation, and tangent point computation for CAD-style corner modifications.

…fillet

Add vertex-based and segment-based chamfer() and fillet() methods with Z/M coordinate interpolation support. Handles both LineString modification and standalone segment operations for CAD-style corner editing.

…operations Handle vertex-based operations on CompoundCurve geometries by preserving existing CircularString segments and properly inserting new chamfer/fillet geometry without segmentation.

…llet

github-actions · 2025-07-10T13:53:32Z

🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit 78972f6)

🍎 MacOS Qt6 builds

Download MacOS Qt6 builds of this PR for testing.
This installer is not signed, control+click > open the app to avoid the warning
(Built from commit 78972f6)

🪟 Windows Qt6 builds

Download Windows Qt6 builds of this PR for testing.
(Built from commit 78972f6)

nyalldawson · 2025-07-13T22:11:45Z

src/core/geometry/qgsgeometryutils_base.h

+     * \param epsilon tolerance for numerical comparisons and intersection detection
+     * \returns TRUE if fillet was successfully created
+     *
+     * \note The caller must ensure that filletPointsX and filletPointsY arrays are


how is that working with the Python bindings? Might be safer to sip_skip this one...

nyalldawson · 2025-07-13T22:12:00Z

src/core/geometry/qgsgeometryutils_base.h

+                               double *trim1StartX = nullptr, double *trim1StartY = nullptr,
+                               double *trim1EndX = nullptr, double *trim1EndY = nullptr,
+                               double *trim2StartX = nullptr, double *trim2StartY = nullptr,
+                               double *trim2EndX = nullptr, double *trim2EndY = nullptr,


shouldn't these all be SIP_OUT too?

nyalldawson · 2025-07-13T22:21:51Z

src/core/geometry/qgsgeometryutils.h

+     * \param y y-coordinate of the point to interpolate
+     * \param segStart start point of the segment
+     * \param segEnd end point of the segment
+     * \param distanceFromStart distance from segment start to the interpolated point


shouldn't this be automatically calculated based on x/y ?

nyalldawson · 2025-07-13T22:22:45Z

src/core/geometry/qgsgeometryutils.h

+     * Interpolates a point on a segment with proper Z and M value interpolation.
+     * \param x x-coordinate of the point to interpolate
+     * \param y y-coordinate of the point to interpolate
+     * \param segStart start point of the segment


change "seg" to "segment" everywhere -- as per https://github.com/qgis/QGIS-Enhancement-Proposals/blob/master/qep-314-coding-style.md#1-naming 1.3

nyalldawson · 2025-07-13T22:23:47Z

src/core/geometry/qgsgeometryutils.h

+
+    /**
+     * Creates a fillet (rounded corner) between two line segments using QgsPoint.
+     * Returns the three fillet arc points via output parameters.


I assume this is a circular arc? I think it should be explicitly mentioned in the docs

nyalldawson · 2025-07-13T22:35:17Z

src/core/geometry/qgsgeometryutils.cpp

+    distance2 = distance1;
+
+  // Validate input parameters
+  if ( distance1 < 0 || distance2 < 0 )


Suggested change

if ( distance1 < 0 || distance2 < 0 )

if ( distance1 <= 0 || distance2 <= 0 )

nyalldawson · 2025-07-13T22:36:31Z

src/core/geometry/qgsgeometryutils.cpp

+  if ( !createChamfer( seg1Start, seg1End, seg2Start, seg2End, distance1, distance2, chamferStart, chamferEnd ) )
+    return nullptr;
+
+  QgsLineString *completeLine = new QgsLineString();


Use unique_ptr. Also use constructor for QgsLineString which takes a list of points instead of calling addVertex multiple times

nyalldawson · 2025-07-13T22:36:43Z

src/core/geometry/qgsgeometryutils.cpp

+  if ( segments <= 0 )
+  {
+    // Return CompoundCurve with circular arc
+    QgsCompoundCurve *completeCurve = new QgsCompoundCurve();


unique_ptr (elsewhere too)

nyalldawson · 2025-07-13T22:37:01Z

src/core/geometry/qgsgeometryutils.cpp

+    QgsCompoundCurve *completeCurve = new QgsCompoundCurve();
+
+    // First linear segment
+    QgsLineString *firstSegment = new QgsLineString();


as above, use constructor instead of multiple addVertex calls (elsewhere too)

nyalldawson · 2025-07-13T22:40:15Z

src/core/geometry/qgsgeometry.cpp

+
+QgsGeometry QgsGeometry::chamfer( int vertexIndex, double distance1, double distance2 ) const
+{
+  const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( d->geometry.get() );


If you want to be more tolerant and also accept multicurves with a single geometry:

Suggested change

const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( d->geometry.get() );

if ( isNull() )

return QgsGeometry();

const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( d->geometry->simplifiedTypeRef() );

elsewhere too

nyalldawson · 2025-07-13T22:41:32Z

@lbartoletti nice work! Above review is about the api and high-level considerations only... I haven't reviewed the actual maths behind the chamfer/fillet geometry creation. I trust you on those! 😆

nyalldawson · 2025-07-13T22:43:26Z

The map tools will be added in a separate PR

Can you elaborate on the plans for exposing these? My personal preference is that they'd be implemented via QgsAdvancedDigitizingToolsRegistry and exposed only in the CAD dock tools panel, as that's the approach with the least ui complexity cost.

uclaros · 2025-07-14T15:04:17Z

src/core/geometry/qgsgeometry.h

+    QgsGeometry fillet( const QgsPoint &seg1Start, const QgsPoint &seg1End,
+                        const QgsPoint &seg2Start, const QgsPoint &seg2End,
+                        double radius, int segments = 8 ) const;


Can you explain why those variants using the segment points are needed?
To me they look weird, as it super easy to call with points that do not match segments or even do not lie on the geometry!

lbartoletti · 2025-07-18T15:02:54Z

@lbartoletti nice work! Above review is about the api and high-level considerations only... I haven't reviewed the actual maths behind the chamfer/fillet geometry creation. I trust you on those! 😆

Thank you!
I'll be AFK for 15 days, but I'll take your comments into consideration when I return.

lbartoletti added 9 commits July 10, 2025 09:17

tests(geometry): add unit tests for QgsGeometryUtilsBase chamfer and …

012f6b0

…fillet

feat(geometry): add chamfer and fillet methods to QgsGeometry

bc7e05f

Add vertex-based and segment-based chamfer() and fillet() methods with Z/M coordinate interpolation support. Handles both LineString modification and standalone segment operations for CAD-style corner editing.

feat(tests): add Python tests for QgsGeometry chamfer and fillet methods

478f918

fix(geometry): preserve curve nature in CompoundCurve chamfer/fillet …

43a4019

…operations Handle vertex-based operations on CompoundCurve geometries by preserving existing CircularString segments and properly inserting new chamfer/fillet geometry without segmentation.

fix(version): replace 3.40 by 4.0 for QgsGeometryUtilsBase chamfer/fi…

302f2bd

…llet

fix(version): replace 3.40 by 4.0 for QgsGeometry chamfer/fillet

e056702

refactor(chamfer/fillet): refactorize interpolation z/m part

3e1a74c

refactor(chamfer/fillet): const'em all

397be51

github-actions bot added this to the 3.46.0 milestone Jul 10, 2025

refactor(chamfer/fillet): move logic to qgsgeometryutils

78972f6

lbartoletti force-pushed the feature/add_chamfer_fillet branch from 481c502 to 78972f6 Compare July 11, 2025 12:55

nyalldawson reviewed Jul 13, 2025

View reviewed changes

nyalldawson added the API API improvement only, no visible user interface changes label Jul 14, 2025

uclaros reviewed Jul 14, 2025

View reviewed changes

	if ( distance1 < 0 \|\| distance2 < 0 )
	if ( distance1 <= 0 \|\| distance2 <= 0 )

-  const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( d->geometry.get() );
+  if ( isNull() )
+    return QgsGeometry();
+  const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( d->geometry->simplifiedTypeRef() );

Uh oh!

Feature/add chamfer fillet #62572

Are you sure you want to change the base?

Feature/add chamfer fillet #62572

Uh oh!

Conversation

lbartoletti commented Jul 10, 2025

Description

Future Work

Uh oh!

github-actions bot commented Jul 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🪟 Windows builds

🍎 MacOS Qt6 builds

🪟 Windows Qt6 builds

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

nyalldawson commented Jul 13, 2025

Uh oh!

nyalldawson commented Jul 13, 2025

Uh oh!

Choose a reason for hiding this comment

Uh oh!

lbartoletti commented Jul 18, 2025

Uh oh!

Uh oh!

github-actions bot commented Jul 10, 2025 •

edited

Loading