[ODE] contact joints / attaching them

[Nate W]

On Fri, 10 Oct 2003, Steve Baker wrote:

> Flavien Brebion wrote:
>
> > I don't see why. The collision detection functions are completely
> > independant of the timestep. Notice that the time step parameter
> > isn't even involved in collisions
> 
> It isn't?   How can the system tell whether a ball thrown at a
> wall - which is on one side of the wall at the start of the timestep
>   - and on the other side at the end of the timestep?

It isn't.  Collision detection is concerned only with the interpenetration
or contact of GEOMETRY objects.  When a collision is detected, a contact
joint must be created between the colliding objects.  After that, it's the
DYNAMICS code that takes the timestep into account when determining how
much force to apply to the BODY objects.

I'm not shouting. :-)  I just wanted to draw attention to the distinctions
between collision detection and dynamics, and between geometries and
bodies.

-- 

Nate Waddoups
Redmond WA USA
http://www.natew.com/