[ODE] Tetrahedron - found it

[Mattias Fagerlund]

> Wow, that's by far the best reference on the subject that I've seen to
> date.
> Thanks!

Glad you liked it, it took me hours of prowling the net to find it ;) 
Any chance anyone on the know could implement those for ODE? Even though 
ODE doesn't support the colission shapes, it would be cool to have the 
masses. Complex shapes can be aproximated with the goems evailable in 
ODE, and so could simple masses I suppose. But adding the correct 
inertia information couldn't hurt...

cheers,
m