Faces parametrization

konstantin_shiriazdanov

I'm trying to implement FS that would make nonlinear transform of solids and surfaces. I'm using evFaceTangentPlanes() to get face parametrization and faced a problem - in some cases (especially for planar faces) a pair of internal parameters (u,v) gives a point within face, but in some other cases the point appears on the face propagation and doesn't belong to the face itself. is it the correct behavior? because i would expect face parametrization to return only points within the face.

Jake_Rosenfeld

@konstantin_shiriazdanov

You are seeing the correct behavior.  The UV parameterization of that face is tied to the UV parameter of the underlying surface, which often does not match the boundary of the face itself. Sorry for the trouble.

konstantin_shiriazdanov

at least i tried

ilya_baran

Yeah, that's a consequence of trimmed surfaces in B-Reps.
You can still filter out points outside the face boundary using qContainsPoint, but that might be slow.

konstantin_shiriazdanov

finally the idea works, though it takes several dozens seconds per transform of a small part (my test snail) but it still is not reliable enough because of face parametrization.