[ODE] one way collisions

[John Millaway]

To simulate a "one way" collision (where one object does not react to 
the collision), the notes (12.10) suggest attaching a contact join 
between the reacting object and the 0 body. I've done this and found 
severe interobject penetration -- not just during the initial collision, 
which is tolerable, but on every subsequent step. In other words, the 
reacting object never escapes the interior of the other object.

Is there another way to simulate to one-way collisions?

-John