- Change pattern eval_sdf to return double (signed distance) instead of pair
- Add reversed parameter to get_local_cap_mat for correct cap orientation
- Add has_end_caps flag to extrude, handle closed axis caps properly
- Add is_closed field to polyline_axis_descriptor
- Use desc.is_closed instead of computing from point/bulge counts
- Fix total_theta calculation in helixline (multiply by two_pi)
- Fix scale vector initialization (zero-fill w component)
Zhicheng Wang