[ODE] Multiple worlds

[Flavien Brebion]

Still in the quest of avoiding tunneling effects, i've come
with a working solution that requires (for performance
reasons) one world per dynamic object.

In the doc it is said that "most applications will only need
one world" and that "different worlds can not collide". Why
is it so ? And is it really true ? I see no direct relationship
between a space and a world; and when doing collisions,
the functions take two spaces in arguments; it has nothing
to do with worlds.

F. Brebion