[ODE] Collision CSG?

[gl]

> I've been wondering about this too but never tried yet: could
> you just invert the contact point's normal and(/or) depth before
> contact joint generation to effectively have objects bounce against
> the inside of a geom instead of its outside...?

I guess in this one case you could.  Actually it would probably be better to
classify primitives as being fully contained by another.  Then, when an
intersection ocurrs, the previous 'contained' state would determine if it
was inside, and thus should have the contact normal reversed.

However, I was thinking about more complicated cases.  Say you wanted an
open goldfish bowl - you could use the two spheres as before, but then also
use a box to slice the top open... in effect you'd have positive and
negative collision primitives.  You would need some way to determine if an
intersection with a positive prim can be disregarded if it's also contained
in a 'negative' collision prim... but that's where my thinking got stuck
: ).
--
gl