[ODE] Trying to create hollow objects

[Chris Ledwith]

> All,
>
> I'm trying to build a simulation of boxes bouncing within boxes within
> boxes.  Essentially, I need a hollow box - something that can properly
> simulate collisions from outside and within.  Since all the
> volume-bounding ODE objects are solid, I'm stuck.
>

<snip>

> Alternatively, is there a simple way to modify ODE to permit hollow
> objects?
>
> Thanks,
> m1ke0

I haven't tried this myself but can't see why it would fail:

Imagine taking a box and attaching 6 boxes to it, one on each side of the
inner box. Now ignore collision between objects inside the inner box with
the box itself - just collide them with the outer 6 boxes. But for objects
outside the box you ignore collision with these 6 boxes and instead
collide with the inner box. You can easily ignore collisions on a geom per
geom basis by organizing them in separate spaces or through proper use of
collision masks (see dGeomGetCategoryBits and dGeomGetCollideBits in the
documentation).

-Chris