Fit continuously connected B-spline surfaces on sampled points with boundary constraints.
Uses my geometry library, my jet-fitting wrapper on CGAL, and my Bézier extraction library.
Requires:
- A curve network (given as B-spline curves)
- Uniformly sampled points in each quad
- Positional and cross-derivative constraints for the outer boundary (given as pairs of B-spline curves) [optional]
Currently the input can be given in a .PWGB file (see pwgb-spec.txt).
The test program generates a single mesh for the surface, and another with the control nets.
The boundary curves of all quads are written to an .OBJ file as polylines.
The surfaces are also exported in .QDS format (see qds-spec.txt).
Command line switches:
| Switch | Meaning |
|---|---|
| --mesh=filename.obj | Use the specified mesh for jet-fitting curvatures |
| --resolution=n | Use the specified resolution for mesh output |
| --preliminary-fit-tangents | Extract tangent length from a preliminary C-1 fit |
| --preliminary-fit-twists | Extract twist vectors from a preliminary C-1 fit |
| --preliminary-fit-normals | Extract normal vectors from a preliminary C-1 fit |
| --extra-knots=n | Add 2n extra knots to the subdividing curves |
| --fit-curves | Fit the quartic curves on sampled points |
| --fit-normals | Fit the cross-derivative curves on sampled normals |
| --coons-patch | Create Coons patches and do not fit to interior samples |
| --cubic-fit=n | Use cubic splines with n inner knots to fit |
| --fix-c0-inside | Fix C0 continuity at the subdivision curves |
| --fix-c0-outside | Fix C0 continuity at the ribbons |
| --retain-boundaries | Retain quad boundaries |
| --retain-direction-blends | Retain the shared direction blends between the quads |
| --retain-ribbons | Retain the original ribbons (scaled unless the fit is cubic) |
| --print-continuity-errors | Print C0 and G1 errors between the quads and to the ribbons |
| --print-approximation-errors | Print C0 and G1 errors to the sampled points and normals |