BoxBox Collision problem

Nov 11, 2007 at 1:52 PM
I'm currently working on / searching for a physics engine for XNA (as you know there are not a lot of working and robust 3D physics engine for XNA) and I just found you project and played with it for some time.
When I created an static box 50x1x50 in the test scene the other smaller boxes act very strange when they hit/collide with this big box. Do you know why this is? Is this a problem with the collision solvers (Gjk?) in general (because I used the BulletX and it seems to have the same scale ratio problem) or it's a bug in your engine, or it can be solved by tuning the parameters?

Nov 12, 2007 at 1:31 PM

Hi KamiSama,

Thanks for reporting this issue. I didn't know this occurred. If you could create a Work Item and attach the changed file (assuming Example1Screen.cs), I'd appreciate it. I'll look at this issue after the next release, which should be soon.

Some things off the top of my head that could potentially be the issue/temporary solution:
  • I'm using a very small scale for the shapes in my example. You may try multiplying the extents of the boxes by a factor of 10. Potentially, precision is being lost.
  • I know of an issue with boxes missing collisions when they both are oriented EXACTLY the same. I don't check for this condition, since it very rare.
Nov 12, 2007 at 6:37 PM
Thanks for reply. I created a work item for that: