Search found 66 matches

by majestik666
Thu Nov 24, 2011 5:40 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: How to detect that which collider in collide...
Replies: 5
Views: 4389

Re: How to detect that which collider in collide...

do a search for contacts callback on the forum
this has been answered many times before :)
by majestik666
Sun Nov 20, 2011 10:05 pm
Forum: General Bullet Physics Support and Feedback
Topic: center of mass not at mesh origin
Replies: 13
Views: 33162

Re: center of mass not at mesh origin

I do this kind of things a lot because of the meshes we get from maya are basically never centered around their pivot. Instead of adding a transform I transform the vertices of the shape so that the vertices are centered around the pivot, and no need for a top transform, once that is done I apply an...
by majestik666
Wed Aug 31, 2011 8:33 am
Forum: General Bullet Physics Support and Feedback
Topic: Intel OpenCL SDK support patch
Replies: 2
Views: 1679

Re: Intel OpenCL SDK support patch

the usual patch process is creating an issue on the google code and attach the
svn patch to it so that erwin can review / publish into the main trunk

F
by majestik666
Sat Aug 27, 2011 4:42 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: btCollisionObject modification added
Replies: 4
Views: 3411

Re: btCollisionObject modification added

no pointer to the world in btCollisionObject is meant
to avoid circular dependencies , so don't think this
will make it ...
by majestik666
Fri Aug 12, 2011 8:14 am
Forum: General Bullet Physics Support and Feedback
Topic: Rigid body callbacks
Replies: 2
Views: 1399

Re: Rigid body callbacks

Check the contact added callback in here :

http://bulletphysics.com/Bullet/BulletF ... ource.html

gives you the pointers to the collisionObjects colliding, good way to find out
what's colliding with what
by majestik666
Tue Jul 19, 2011 12:38 am
Forum: General Bullet Physics Support and Feedback
Topic: On the meaning of CollisionFlags
Replies: 5
Views: 2469

Re: On the meaning of CollisionFlags

CF_CUSTOM_MATERIAL_CALLBACK is designed so that you can change the collision response per face on an object. you will get a callback from bullet when a contact happens with this object. You can also use the contact information to derive other stuff, like glue/facturing/particle emission etc Check th...
by majestik666
Sun Jul 17, 2011 9:00 pm
Forum: General Bullet Physics Support and Feedback
Topic: How do I remove object from World more quicker?
Replies: 7
Views: 4695

Re: How do I remove object from World more quicker?

Although this should work, bullet still needs faster code
to remove a lot of objects without removing them all....
by majestik666
Sat Jul 16, 2011 2:16 am
Forum: General Bullet Physics Support and Feedback
Topic: How do I remove object from World more quicker?
Replies: 7
Views: 4695

Re: How do I remove object from World more quicker?

I haven't spent too much time timing this in bullet, but I suspect very much that the removeOverlappingPairsContainingProxy call in the destroyProxy function will take a lot of time when destroying a lot of objects... we have scene with 300,000+ objects and it's pretty long. Will try and come up wit...
by majestik666
Sat Jul 09, 2011 11:45 pm
Forum: General Bullet Physics Support and Feedback
Topic: Very slow cleanup.
Replies: 7
Views: 3058

Re: Very slow cleanup.

We do have the same kind of issues with very slow reset/cleanup. I can think of a big sim (~300,000 objects i believe) and it is taking a few minutes to actually reset the simulation. I did quite a lot of profiling to see where the time was gone and it's actually the removeRigidBody that is taking 9...
by majestik666
Sun Jun 12, 2011 12:12 am
Forum: General Bullet Physics Support and Feedback
Topic: How to add angular velocity to a soft body
Replies: 4
Views: 2126

Re: How to add angular velocity to a soft body

there's no such thing for soft bodies...
in our implementation you can apply velocities by calculating
the proper velocity for each node in the soft body.
it's not a one line thing but still pretty easy/fast to implement

Francois
by majestik666
Thu May 19, 2011 8:57 pm
Forum: General Bullet Physics Support and Feedback
Topic: Generic6DofConstraint - strange behaviour of y-axis - jitter
Replies: 4
Views: 2912

Re: Generic6DofConstraint - strange behaviour of y-axis - ji

the generic6Dof constraint is limited to -180 180 on the y axis
as far as i can remember, if you want rotation only on the y axis
you can either rotate the constraint or use a hinge constraint.

F
by majestik666
Tue May 03, 2011 5:18 am
Forum: General Bullet Physics Support and Feedback
Topic: determinism after stepSimulation and insert e rigidBody
Replies: 3
Views: 1943

Re: determinism after stepSimulation and insert e rigidBody

just out of curiosity, what was the problem / solution ?
by majestik666
Wed Apr 27, 2011 1:46 am
Forum: General Bullet Physics Support and Feedback
Topic: Does Bullet rely on double precision operations?
Replies: 5
Views: 2091

Re: Does Bullet rely on double precision operations?

Not related to the original post but, is there any place in bullet where even when compiled for doubles bullet uses float numbers ? I haven't had much time to look deeper into it but recently figured out that compiling as double was giving me non-deterministic solves in some situations and it was de...
by majestik666
Thu Mar 24, 2011 1:11 am
Forum: General Bullet Physics Support and Feedback
Topic: glue/fracture determinism
Replies: 9
Views: 4120

Re: glue/fracture determinism

it's actually a very simple scene , which was quite surprising when I saw that it was not deterministic (see attached image) a sphere or radius 1, mass 100 at (0,15,0) 4 cubes 1 unit , mass 1, wide slightly penetrating 1 ground cube 20x5x20 (passive) this will lead to very different results everytim...