a spline? In a more general setting of semi-algebraic sets there is the Tarski-Seidenberg Theorem http://en.wikipedia.org/wiki/Tarski%E2%80%93Seidenberg_theorem that says the projection of a semi-algebraic set is itself a semi-algebraic set. As nurbs surfaces and breps defined by them are semi-algrbaric sets this means that the projection must be reasonably nice. I could not discover whether it is always a spline. There are however reasonably nice ways to get splines from algebraic curves, though we are back to an approximation. It would be nice to have an algorithm that is guaranteed to give the precise splines when they exist (as in the example above) and will otherwise give a good approximation, I was not able to find if one has been written, even in the theoretical literature.…
d files have surface divided into rectangular grid, I want that grid hexagonal SO THAT I CAN ATTACH MY HEXAGONAL GEOMETRY IN IT.Hexagon Pattern.3dm,,,,Hexagonal Pattern.ghx…