Definition: Object defined by F>=0, where F is a B-spline function of three variables
- Control points of the cubic B-spline volume. Only the fourth coordinnate is used
: Cubic BSpline blending function.
x - point coordinates
l,m,n - number of control points on each axis
bbox - array defining the bounding box of the object
ctr_pts - array of values for each control point
Test file: bsplinef.hf