BRepMesh_IncrementalMesh creates incorrect mesh

I have a NURBS surface bounded by a single spline edge.
On the attached image you can see the green triangulation deviating significantly from the red spline curve.
The triangulation is done using an absolute deflection value of 20.0 and an angular deflection of 0.1*PI
The smaller the angular deflection, the worse the error.

In the next message, a BRepTools::Write dump of the face causing the error is attached.

Fabian Hachenberg's picture

here's the dump

Forum supervisor's picture

Hi Fabian,
This shape has incorrect pcurve. See the attached picture1.
It has C1 continuity, while the 3D curve has C0 continuity.
Pcurve was probably obtained by automatic projection with fixshape.
This method gives wrong projection. The good face (attached to the next post) may be obtained from the original one, using another projection function, that is under DRAW command 'project'. Using this face the triangulation is correct.

Forum supervisor's picture

the good face is attached.