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PostPosted: Sun Mar 25, 2012 7:46 pm 
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Joined: Wed Mar 07, 2012 6:07 pm
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Hello,

I want to create objects that don't collide with eachother but at the same time have a collision detection, so that I can use collision callbacks. What's the difference between having a GhostObject with collision flag CF_NO_CONTACT_RESPONSE and a RigidBody with that same flag? And also, what if I want 2 balls to collide with the walls and floor in a room, but not with eachother?

Thank you


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PostPosted: Mon Mar 26, 2012 8:33 am 
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ghost objects retain their own contact manifold, whereas non-ghost objects have their contact information in the default contact manifold.


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PostPosted: Tue Mar 27, 2012 8:14 pm 
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Karrok wrote:
ghost objects retain their own contact manifold, whereas non-ghost objects have their contact information in the default contact manifold.


I don't even know how to interpret that. Could you elaborate, please.


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PostPosted: Wed Mar 28, 2012 11:57 pm 
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So if my objects are Ghosts, will they still have normal RigidBody collision reactions made in bullet?

And would I be able to test if they're colliding with another object? I coded a working callback to get collision events but I want to be able to also know when the collision stops (ie, when two objects that were colliding move away from each other)


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PostPosted: Thu Mar 29, 2012 2:15 am 
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Quote:
but I want to be able to also know when the collision stops (ie, when two objects that were colliding move away from each other)


Couldn't you just do a dot product on their directional vectors to determine that?


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PostPosted: Fri Mar 30, 2012 11:30 am 
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You mean they're orientation? So they only collide if the dot product is positive? That would work if you had a car bumping into another car from behind, what about front to front?

I dont think that is the solution.


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