[ODE] geoms having the same position

Aras Pranckevicius nearaz at gmail.com
Tue Oct 4 15:01:59 MST 2005

>  I've 1223 geoms having the same position (all are in one hash space,
>  and NearCallback contents are commented so ther shouldn't be any
>  collision checking for that geoms) and it all runs VERY SLOW (frame per minute or so...).

In ODE hashspace implementation, the hash space is rebuilt every step
(frame). So while in the end the NearCallback does nothing, it still
goes through each geom, hashes it and inserts into internal hashspace
structures, then goes through all nearby pairs (in your case it's over
million pairs - because each geom potentially collides with each
other) just to call the empty callback.

There's not that much you can do about that. Quadtree space does not
rebuild the tree each frame, but would still check these million
pairs, so it should not magically help.

So, the question is... why do you need a thousand geoms in one place?

Aras 'NeARAZ' Pranckevicius
http://nesnausk.org/nearaz | http://nearaz.blogspot.com

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