[ODE] Trimesh questions

David Walters hidden.asbestos at googlemail.com
Tue Oct 3 08:33:32 MST 2006

> I have a few questions about trimesh usage.  Are the vertices provided to
> dGeomTriMeshDataBuildSingle considered to be in world coordinates or local?
> Does the position/rotation of the trimesh geom modify these vertices or is
> this information ignored?  Will a TransformGeom have any effect on the
> vertices?

The vertex positions are local WRT to the geom/body transform. The
vertex data is not modified.

> It looks like ODE only keeps around the pointer passed in with the verts and
> doesn't copy all of the verts, so if the application wants to update the
> position of the verts in the mesh, does it need to do anything other than
> modify them directly in the array?  I noticed there was a function I
> couldn't find documentation for called dGeomTriMeshDataUpdate that looked
> like it might be useful for this purpose.

I'd be wary here as internally some structures are created to make
collisions more efficient. I'm not sure about the details though and I
guess some kind of recalculate function might be in there or it's
certainly something that would be a useful feature.


More information about the ODE mailing list