BSPLINE_INSERT_INTERPOLATION_POINT inserts interpolation points into a specified B-spline.
---->(BSPLINE_INSERT_INTERPOLATION_POINT)----|B-spline|----+ | +---------------------------<--------------------------+ | | +----------------<------------------+ | | | +--+--|point|----|enter new position|--+---->
BSPLINE_INSERT_INTERPOLATION_POINT [pick new interpolation point]