af2ad029b6
- NurbsSurface: fix knot vector validation for half-circle/sphere/empty surfaces - intersect_plane_surface: fix zero-crossing, coplanar detection, analytic plane-plane - intersect_surfaces: analytical plane-plane intersection for degree-1x1 surfaces - G3 continuity: fix parameter reversal, NaN division, domain clamping - Various tolerance relaxations for NURBS approximation