[ODE] Introducing myself... and a possible bug

Ignacio García Fernández ignacio.garcia at uv.es
Mon Nov 17 10:31:05 MST 2003

On Fri, Nov 14, 2003 at 08:14:09PM +0000, Adam D. Moss wrote:
> Ignacio García Fernández wrote:
> >The problem appeared whe detecting the collision between a pair of boxes.
> >I they are almost parallel and collide edge against edge the contact point
> >is detected somewhere in the common edge but far away from the boxes.
> ...
> >+  if (d <= 0.0001) {
> Applied.  Thanks!
> Was this epsilon value chosen while working with single or
> double precision?  It might make sense to use a different epsilon
> here (and potentially in other places in ODE) depending on the
> precision of a dReal.

Well, actually this value was taken by trial and error. The reason is that
for values lower than 0.0001 the position of the contact point is quite
far away. Indeed with this value I still find some problems, but I have
solved them by a post processing of the contact point: I reduce
the value of each component of the point in relative coordinates, to the
length of the edge of the box.

However I don't think this is a solution but a patch :-)

Thank you for your response.



May the source be with you
Ignacio García Fernández                       Instituto de Robótica
<ignacio.garcia_at_uv.es>                    Universidad de Valencia
http://robotica.uv.es/~ignacio/                     Tlf. 96 354 3564

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