Alain wrote:

> Using an array of transforms would be wastefull. It would uselessly use 
> extra memory. It would make rendering slow as the whole array will need 
> to be computed for every ray that encounter the object, as well as any 
> CSG operation that use that object. That array will need to be dynamic 
> as you can never tell beforehand how many transforms will be applyed to 
> any particular object, adding some useless overhead, and requiring still 
> more memory.

One reason you would need more then one forward or reverse transform 
during rendering is if the renderer were to support motion blur.  One 
transform stipulates the start-of-frame positioning of the object, and 
the other stipulates the end-of-fram positioning (you could even have a 
spline of transforms if you didn't want to linearly interpolate between 
the start and end, but that may be too hairy to be worth the trouble).

Regards,
John

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