Search found 169 matches

by ola
Mon Aug 31, 2009 8:17 pm
Forum: General Bullet Physics Support and Feedback
Topic: noob trying to figure out static object collisions
Replies: 3
Views: 2030

Re: noob trying to figure out static object collisions

You need to set the restitution values for the static objects too. The default value is 0 which means no bounce.

When colliding, the restitution values for the two colliding bodies is combined by multiplication, so if one of them is zero, the result is zero, no matter what the other value is.
by ola
Mon Jul 27, 2009 9:29 am
Forum: General Bullet Physics Support and Feedback
Topic: SVN rev. 1715 on Mac with double precision is broken..?
Replies: 2
Views: 1199

Re: SVN rev. 1715 on Mac with double precision is broken..?

Hi Erwin!

Yes that fixed it :-) Thanks for the swift fix!

Ola
by ola
Mon Jul 27, 2009 12:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Can someone explain RigidBody.setSleepThresholds() to me?
Replies: 2
Views: 1084

Re: Can someone explain RigidBody.setSleepThresholds() to me?

It's velocities. When the rigid body moves slower than the threshold value, it goes to sleep.

If your units are meters, then the linear part is in meters/second. The angular bit is in rad/s.

Best regards,
Ola
by ola
Mon Jul 27, 2009 12:15 am
Forum: General Bullet Physics Support and Feedback
Topic: SVN rev. 1715 on Mac with double precision is broken..?
Replies: 2
Views: 1199

SVN rev. 1715 on Mac with double precision is broken..?

Hi, I just installed Bullet from SVN on a new mac, and built it in double-precision mode. It seems that the collision detection is not working at all. For example, shooting boxes in any demo makes them just fly through everything. Single-precision mode works just fine, by the way. I compared by buil...
by ola
Thu Jul 02, 2009 9:31 pm
Forum: General Bullet Physics Support and Feedback
Topic: Body inside another body
Replies: 6
Views: 2359

Re: Body inside another body

For the cell's shell you'll have to use some shape that is hollow, so the only thing I can think of is a mesh shape. The mesh triangles are double sided and "paper thin". If the cell body is static, you can use the btBvhTriangleMeshShape. (if you want it dynamic, maybe the btConvexTriangleMeshShape ...
by ola
Wed Jul 01, 2009 9:53 pm
Forum: General Bullet Physics Support and Feedback
Topic: btConcaveShape implementation question
Replies: 2
Views: 1083

Re: btConcaveShape implementation question

I use the btBvhTriangleMeshShape for my terrain system. The terrain is divided into tiles that are 4x4 km each, with one shape for each. This way I can load terrain on demand (add/remove tiles). So I'm not sure you really have to create your own concave shape, the Bvh shape is pretty fast for static...
by ola
Fri Jun 26, 2009 8:35 am
Forum: General Bullet Physics Support and Feedback
Topic: CMakeLists.txt missing files
Replies: 2
Views: 1048

Re: CMakeLists.txt missing files

Yes it's recommended to submit patches there, so they won't get lost in all the forum postings.
by ola
Fri Jun 12, 2009 8:39 am
Forum: Applications, Games, Demos or Movies using Bullet
Topic: BotApp - robot fighting game
Replies: 4
Views: 9142

Re: BotApp - robot fighting game

Really nice!!

I ran it under Linux with wine, that worked just fine, by the way.

I was wondering, do you use raycast-based wheels or actual wheels as rigidbodies with constraints?

Best regards,
Ola
by ola
Thu Jun 11, 2009 2:18 pm
Forum: Release Announcements
Topic: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints
Replies: 13
Views: 27121

Re: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints

Thanks, can you try out Bullet 2.75 RC2?
Yes, it works fine now! :-) Thank you.
by ola
Thu Jun 11, 2009 11:01 am
Forum: Release Announcements
Topic: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints
Replies: 13
Views: 27121

Re: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints

I just tested the RC1 (svn 1691), and I think I might have a problem with static rigid bodies. We depend on switching the rigid bodies from dynamic to static and back (by removing, re-adding with or without mass). Previous behaviour for these was that they are added to the world and show up as activ...
by ola
Tue Jun 09, 2009 1:52 pm
Forum: Release Announcements
Topic: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints
Replies: 13
Views: 27121

Re: Bullet 2.75 beta1: GPU, SPH fluids preview, new constraints

Just a small reminder for this tiny fix :-)
http://www.bulletphysics.com/Bullet/php ... f=9&t=3599

(virtual definition of addCollisionObject / removeCollisionObject in btCollisionWorld.h)

Best regards,
Ola
by ola
Tue Jun 09, 2009 1:50 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bug - raycast hit normals on rotated compound child shapes
Replies: 1
Views: 901

Re: Bug - raycast hit normals on rotated compound child shapes

Small update, I made a patch with a fix suggestion, see the issue tracker.
by ola
Tue Jun 09, 2009 11:45 am
Forum: General Bullet Physics Support and Feedback
Topic: Bug - raycast hit normals on rotated compound child shapes
Replies: 1
Views: 901

Bug - raycast hit normals on rotated compound child shapes

I ran into weird problems with my own raycast-based vehicle recently, and just found the reason why. Some assets in my game world are static mesh shapes, rotated within a compound shape. Raycasts hitting these objects return normal vectors that don't seem to take the child shape rotation into accoun...
by ola
Sun May 31, 2009 2:43 pm
Forum: General Bullet Physics Support and Feedback
Topic: "Bouncy" Elevators
Replies: 2
Views: 1085

Re: "Bouncy" Elevators

Sounds like you get some penetration between the sphere and platform initially before their speeds match. If you know the sphere is resting on the platform, try setting it's linear velocity to the same as the platform when starting to move the platform. Alternatively, maybe you can try to slowly ram...