System information

SolveSpace version:

Operating system: All

Expected behavior

Make a helical extrusion from a rectangle and look at the triangle mesh.

Actual behavior

For meshes over 90 degrees there are periodic defects in the triangle mesh and at the ends.

Additional information

These defect appear because edges (trim curves) are broken into PWL segments independent of the surface. Straight lines have no need to be broken up as they lie perfectly on the surface. We should use the same subdivision algorithm as grid triangulation when doing a helical extrusion of a straight edge.

This helix is over 90 degrees, so is composed of 2 section. The seam is clearly visible.