[ODE] Composite Geom and Joints

[Don Burns]

ODEers,

I discovered ODE a few weeks ago and have been enjoying the fruits of the 
labor put into it for a while now.  Thanks to the authors and contributors 
for a great project.

I'm developing a WWI flight simulator.  I've described my airplane models 
as a composite geometry made of spheres placed at each of the contact 
points (wheels, tail, wing-tips, nose, etc.).  This seems to work well for 
doing collisions.

I spent the last couple of days trying to get familiar with using joints 
as I want to add wheels to the model.  I started by modifying the 
test_buggy example.  After several experiments, it seems that I can't get 
joints to work properly with a body that has composite geometry.  So, for 
example, if I replace the box in the example with a composite geometry 
model, it seems that the composite geometry no longer works in collisions.  
The result I see is my airplane "hanging" from its wheels beneath the 
surface of the ground.  The wheels (joints) are intersecting correctly, 
but not the rest of the geometry.

A couple of questions, then.  

1) Am I using the right approach in describing my models with composite 
geometry?  (Seemed the fastest course of action without having to learn 
how to make my own geometry).

2) How do I get joints to work with my composite geometry?

Thanks!

-don