Told you it wasn't easy, (Physics based net) no matter hows you approach it ;)
Anyway, not sure if you ever got my cubic spline functions? If not, i'll have a look for them. Iirc you used them like,
Value#=Cubic(p1#,p2#,p3#,p4#,position#<0 to 1>) (Just repeat for all dimensions)
So...shouldn't be too hard to drop into your code or you know get the concept behind it to write your own.
Anyway, not sure if you ever got my cubic spline functions? If not, i'll have a look for them. Iirc you used them like,
Value#=Cubic(p1#,p2#,p3#,p4#,position#<0 to 1>) (Just repeat for all dimensions)
So...shouldn't be too hard to drop into your code or you know get the concept behind it to write your own.