On Thu, 14 Mar 2002 09:40:37 -0600, Christopher James Huff
<chr### [at] maccom> wrote:

>Try unevenly scaling a sphere. A vector from the center to a point on 
>the surface (the normal of an unscaled sphere) goes one way, but the 
>normal goes the opposite direction. And how about shearing a box? You 
>will end up slanting the normal of the sides which don't change 
>orientation.

Well, what I do is inverse-transform the point of intersection
(accounting for translation) so that it is in the object's own
coordinate sphere, then use a simple formula to determine the normal
of a unit object, then transform that normal back to global space
(ignoring translation, of course). This works. And of course it might
just turn out that I am doing what you're doing, only slower <g>. I
need to explore this better.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message