> Hmm I don't think nonlinear transformations would cause the ray to be a
> curve.

Of course they would, if I apply the following transformation to a sphere:

x -> x
y -> y^3
z -> z

Then it's impossible to convert this to a "straight ray intersecting with a 
unit sphere at the origin" problem, which is what POV does for all linear 
transformations.

> Non-linear transf. are already possible in isosurfaces.

Yes, and they are much slower than rendering primitives like a sphere and 
take setting up to get correct results.  Primitives just work, fast.

Post a reply to this message