问题
How to reconstruct a B-spline surface's 4 sides to 4 B-spline curves?
ps: It should be similar to Autodesk Alias's Duplicate Curve Tool, where you can select any U/V on a surface and rebuild a degree 3 B-spline curve. I don't know what's the algorithm behind.
回答1:
The 4 boundary curves of a B-spline surface can be constructed easily as B-spline curves by using the first/last row or column of control points and corresponding degree and knot vectors. For example, the boundary curve in u direction at v=0.0 is a B-spline curve constructed using degree and knot vector in u direction and the first row of control points.
来源：https://stackoverflow.com/questions/61941442/how-to-reconstruct-a-b-spline-surfaces-4-sides-to-4-b-spline-curves