disable collisions

[fboy]

how do i disable collisions between a group of objects?

what i want is to add a new set of objects to the world that will collide with everything except each other.

i have used getBroadphaseProxy()->m_collisionFilterGroup to give them all their own group, but if i set m_collisionFilterMask to zero then they won't collide with anything at all, and if i leave it as is, then they will collide with everything (including themselves)

how should i be setting this up?

[pico]

For games you will run soon into collision filter problems that can't be matched by Bullets functionality.
I suggest you do your own collision match system and implement an own customNearCallback.

void customNearCallback(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, btDispatcherInfo& dispatchInfo)
{
..your collision match system here..
// if objects should have normal bullet collision:
dispatcher.defaultNearCallback(collisionPair, dispatcher, dispatchInfo);
}

bltDispatcher ->setNearCallback(yourCustomNearCallback);

[fboy]

great, thanks for the tip pico, its all working fine now, just a bit of a shame there wasn't "out of the box" support from bullet..

[chunky]

Bullet can do it based on collision masks, I documented it here: http://chunkyks.com/bulletthings.pdf

Gary (-;