find normal vector in b-spline surface

Dear Sir!

I would like to know normal vector in b-spline suface.

In Plane, To use member fuction, I find ease the value.

But how can i find normal vector in b-spline surface?

If my though mistake, How do i solve it ?

And Can i convert b-spline surface to plane ?


kim wj's picture

All surfaces in OCC inherited from geom_surface. So, you don't have to think of the type of surface. Just call DO,D1,D2 or D3 memeber fucntions in goem_surface as you did it in goem_plane. Unless you mean approximation, It is impossible to convert geom_bsplinesurface into geom_plane,