[ODE] Collisiondetection with triangles
David Walters
hidden.asbestos at googlemail.com
Fri Mar 16 09:49:29 MST 2007
Hi,
> already read the documentation and i think i misunderstood something. For a
> plane, therefore I need the normal vector of that plane and some factor
> (d?).
> First of all I thought a,b,c,d are just vectors and the planes edges are
> placed at the coordinates for a,b,c,d.
No, the plane primitive in ODE is a mathematical plane - i.e. infinite in area.
Parameters a, b, c, d are all scalar values representing the plane such that
a * x + b * y + c * z + d = 0
for any point (x,y,z) on the plane. To put it a bit more simply, a
normal: (a,b,c) defines a direction and 'd' the distance from the
origin (typically a negative value in my experience)
If you want some more detail beyond the basics, maybe this with help:
http://mathworld.wolfram.com/Plane.html
> So with that circumstance the only way for checking a ray's collision with a
> single triangle is a trimesh.
>
> Or does anyone of you has better ideas?
The only way to do this in ODE currently is to create a trimesh with 1
triangle in it.
I'm not sure if the overhead of a trimesh is significant enough to
warrant a single triangle collider...
Regards,
David Walters
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