Optimizing collision detection for a large heightfield

[linksan]

Hi,

I'm working on a simple racing game and am using a btHeightfieldTerrainShape as the ground. With a heightfield of 128x128 (as in the vehicle demo) my game runs at full speed. When I increase the mesh size to 256x256 or greater the game slows down.

Is it possible to ignore collisions outside of a certain radius of the car?
Or to create a ~20x20 dynamic heightfield that moves with the car and changes shape based on it's location?

Any help or a nudge in the right direction would be greatly appreciated

Thanks in advance

[Erwin Coumans]

Have you profiled which part of the game exactly slows down?

Large heightfields shouldn't slow-down the game. If so, we need a reproduction testcase to figure out what is wrong.
Thanks,
Erwin