> As it is stated there only linera_spline is ineterpolation. b_spline and
> cubic_spline is aproximation.

To my knowledge cubic splines do have the interpolation property.
For four points p1 to p4 the cubic spline is a third order polynomial
curve that goes through p2 and p3 such that the tangent at p2 is
parallel to the line p1p3 and the tangent at p3 is parallel to the
line p2p4. A b-spline is also a third order polynomial curve, but it
does not go through p2 and p3. It is optimized to go as near p2 and p3
as smoothness allowes, but I don't know exactly.
For more points p1 to pn both splines are the concatenation of the
respective splines for p1 to p4, p2 to p5,..., and p(n-3) to pn.


-- 
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer

Post a reply to this message