Search found 22 matches
- Wed Aug 08, 2012 11:14 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Changing the shape of a rigid body (opening a door in wall)
- Replies: 3
- Views: 4905
Re: Changing the shape of a rigid body (opening a door in wa
Hi, What would be best practice here? - Remove the RigidBody from the collisionWorld and add a new one when door opens/closes - track it outside the world by reference and somehow manipulate the sub shape (I'm assuming this will need a CompoundShape) Is there some other approach that is better? Usu...
- Mon Aug 06, 2012 1:12 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Constraints for wheels
- Replies: 6
- Views: 8727
Re: Constraints for wheels
In your opinion is it possible at all to simulate a vehicle using actual turning cylinders as wheels in Bullet? I thought most people doing vehicle simulations did a hack when modelling wheels, so they seem to spin by the renderer, but in the physics engine they are just collision-detection cylinder...
- Mon Aug 06, 2012 1:08 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Incorrect ConvexSweepTest LocalConvexResult
- Replies: 5
- Views: 5264
Re: Incorrect ConvexSweepTest LocalConvexResult
monkeyman: Thanks for the reply. As far as I've found thus far my suspicions were correct, at least its giving me normals correct enough to work with. I've had to change my navigation method for the Controller I'm working on due to the narrow margins of collision i'm working with, which sweeps unti...
- Sat Jul 28, 2012 10:43 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: ConvexSweepTest Keeps Failing
- Replies: 5
- Views: 6579
Re: ConvexSweepTest Keeps Failing
As a side-note, the btKinematicCharacterController has the same bug, it updates positions of the character without recalculating the AABBs and hence will miss interpenetrations.. Hello, how you update the ghost object AABBs for the btKinematicCharacterController? Thank you Bruno You need to put som...
- Thu Jul 26, 2012 9:32 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Changing postition of a kinematic body and missed collisions
- Replies: 5
- Views: 5765
Re: Changing postition of a kinematic body and missed collis
The user input device I'm using sends the change in position from the last packet, so the kinematic bodies do not necessarily move in small steps. Fast movement from the user means larger steps from one spot to the next. My theory on this is that it seems like bullet is treating them as though they...
- Thu Jul 26, 2012 8:44 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: ConvexSweepTest Keeps Failing
- Replies: 5
- Views: 6579
Re: ConvexSweepTest Keeps Failing
Okay, I solved the issue. Turns out this is a fundamental issue with our implementation of a kinematic bullet environment: updateAABBs needs to be called when anything moves in the world. Normally, this is taken care of inside tick(), but since we are using bullet merely for kinematic collision che...
- Mon Jul 23, 2012 9:41 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Incorrect ConvexSweepTest LocalConvexResult
- Replies: 5
- Views: 5264
Re: Incorrect ConvexSweepTest LocalConvexResult
To update, it appears that the ConvexSweep is returning the triangle face normal I was trying to get manually. Broadphase results vs a BVH force you to locate the triangle and calculate the normal yourself, as the normal returned in the manifold is the "Separating" normal in world space. ...
- Thu Feb 23, 2012 11:23 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: "Sticky" objects
- Replies: 1
- Views: 3145
Re: "Sticky" objects
i found this behaviour when I ran code within one of the bullet demos which had enabled the continuous collision detection. after an object collided with a compound shape, it could stick there for a second, then move a bit, then stick again, then continue moving... check if you have some of the cont...
- Wed Feb 22, 2012 12:10 am
- Forum: General Bullet Physics Support and Feedback
- Topic: [Feature request] method to provide collision object index
- Replies: 1
- Views: 3207
Re: [Feature request] method to provide collision object ind
normally, objects are added and removed all the time to the world, so the actual indices in the internal arrays are not really meaningful... i would say that the user pointer system in this case actually seems like the best way to get your ogre index back. just set the user pointer in the bullet col...
- Wed Feb 01, 2012 10:50 am
- Forum: General Bullet Physics Support and Feedback
- Topic: best way to make a helicopter?
- Replies: 2
- Views: 6640
Re: best way to make a helicopter?
Actually the pitch of the blades are varied throughout the rotation by a mount called the swashplate, so the blades can for example develop more lift on the left side of the helicopter than the right. The controls of the heli shift this asymmetry to develop thrust laterally. The pitch can also be va...
- Tue Jan 17, 2012 9:46 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Bullet 2.77 Restitution issue.
- Replies: 8
- Views: 11027
Re: Bullet 2.77 Restitution issue.
What it tries to do when penetration is larger than 0 (which is what happens when an object is almost but not quite touching another) is calculate the change in velocity required so that collision occurs exactly on the next time step. But that only works if the restitution speed is zero. When there...
- Mon Jan 16, 2012 8:08 am
- Forum: General Bullet Physics Support and Feedback
- Topic: SoftBody Bunny Car Demo
- Replies: 3
- Views: 4404
Re: SoftBody Bunny Car Demo
Thanks, for the reply monkeyman and this is the demo with the bunny going down the staircase. What you have mentioned. That was my first imppresion that the wheels were somehow rubbing against each other Makeing the vehicle unstable. But this is not the case What is Happening is when the Motorcontr...
- Sat Jan 14, 2012 3:23 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: SoftBody Bunny Car Demo
- Replies: 3
- Views: 4404
Re: SoftBody Bunny Car Demo
Hello Everyone in The Bunny Car sample when the m or n key is pressed and held down the car pops a wheelie and spins out of control why dose this happen and how can this be fixed I tried Using applyForce on the Vehicle thinking it might apply some downward force to the Vehicle and stop the body fro...
- Tue Jan 10, 2012 10:34 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Emulating energy-loss in collisions
- Replies: 0
- Views: 2501
Emulating energy-loss in collisions
Hi, is there a built-in method in Bullet to emulate inelastic energy-loss in collisions? Lets say I have two concrete blocks colliding, in bullet they will, if hit on say a corner, start to spin wildly, while in real life they would never do that, a collision imparting that amount of impulse would j...
- Mon Jan 09, 2012 12:12 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: split or merge static geometry before broadphase?
- Replies: 0
- Views: 2407
split or merge static geometry before broadphase?
Hi, this is in the Bullet wiki: Other Tips For Increasing Broadphase Speed If you have a large amount of static trimesh collision shapes, batch them together using a single btBvhTriangleShape. This will only have one entry in the broadphase. Could someone weigh in with pros and cons here? Since norm...