For now, please try using collisionFilterGroup/collisionFilterMask, or override the virtual 'needsCollision' in your derived version of btCollisionDispatcher.
See http://continuousphysics.com/Bullet/php ... .php?t=712
I plan on adding a 'nearCollisionCallback', for better control.
Thanks for the feedback,
i think this flag is set the object whether or not be collision.
but i have no idea that how to set the flag.
for example,i have 3 object,i want object1 can not collision with object2,
but object1 can collision object3, how can i set the flag?