[ODE] Can't seem to make parallel opposing planes

[Geoff Carlton]

Have you tried:
  dCreatePlane (space,0,0,1,0);
  dCreatePlane (space,-1,0,0,-1); 
  dCreatePlane (space,1,0,0,-1);

The "buggytest" demo has 6 opposing planes (making a cube) and that 
works fine.

Geoff