griefith/test
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

Curves: Enhance tesselation of NURBS with corners

Browse Source 
Current NURBS evaluation handles corners or sharp angles poorly. Sharp
edges appear when a knot vector value is repeated `order - 1` times.
Users can make sharp corners by creating NURBS curve with `Bezier` knot
mode or by setting `order` to 2 for legacy curves. The problem occurs
because current algorithm takes all the curve's definition interval,
divides it into equal parts and evaluates at those points, but corners
are exactly on repeated knot's. To hit those, the resolution has to be
increased higher than required for the rest of the curve.

The new algorithm divides non zero length intervals between two adjacent
knots into equal parts. This way corners are hit with a resolution of 1.
This does change the evaluated points of NURBS curves, which is why some
test results have to be updated in this commit.

Pull Request: https://projects.blender.org/blender/blender/pulls/138565
This commit is contained in:
Laurynas Duburas
2025-06-12 16:22:21 +02:00
committed by Hans Goudey
parent e9bb58e6df
commit 3c407ebeaa
17 changed files with 147 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tests/python/bl_usd_export_test.py
View File

@@ -936,7 +936,7 @@ class USDExportTest(AbstractUSDTest):
# Contains 2 NURBS curves
curve = UsdGeom.NurbsCurves(stage.GetPrimAtPath("/root/NurbsCurve/NurbsCurve"))
check_nurbs_curve(curve, False, [4, 4], [6, 6], 10, [[-1.75, -2.6898, -1.0117], [3.0896, 1.9583, 1.0293]])
check_nurbs_curve(curve, False, [4, 4], [6, 6], 10, [[-1.75, -2.6891, -1.0117], [3.0896, 1.9583, 1.0293]])
# Contains 1 NURBS curve
curve = UsdGeom.NurbsCurves(stage.GetPrimAtPath("/root/NurbsCircle/NurbsCircle"))