Search found 84 matches
- Tue Oct 16, 2018 3:05 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Strange behavior of rigid bodies (video) C++
- Replies: 7
- Views: 9532
Re: Strange behavior of rigid bodies (video) C++
Looks like your multiplication order is the wrong way round
- Mon Oct 15, 2018 9:36 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Strange behavior of rigid bodies (video) C++
- Replies: 7
- Views: 9532
Re: Strange behavior of rigid bodies (video) C++
You didn't respond to my suggestion to check your maths. The best ways to do that are to 1. Look at it and check that your code matches what you wrote down on paper 2. Feed it simple input, and check that the output is what you expect. In this case, the output of your maths is a rendered object, and...
- Sat Oct 13, 2018 12:21 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Strange behavior of rigid bodies (video) C++
- Replies: 7
- Views: 9532
Re: Strange behavior of rigid bodies (video) C++
Just from the video - it looks like you're rendering your shapes offset (a long way) sideways from the actual physical objects. That would explain why initially they look OK when they fall - the real stack would be some distance to the side. But when the objects start falling and rotating, your rend...
- Tue Jul 31, 2018 4:25 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btHeightfieldTerrainShape going nuts
- Replies: 8
- Views: 28899
Re: btHeightfieldTerrainShape going nuts
It's odd looking at this old code again! You can set the contact added callback from btManifoldResult.cpp: ContactAddedCallback gContactAddedCallback=0; I set mine to this: //---------------------------------------------------------------------------------------------------------------------- bool C...
- Thu Oct 19, 2017 11:43 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Vs2015 Build failure - unicode problems
- Replies: 1
- Views: 5790
Re: Vs2015 Build failure - unicode problems
In addition - the make system makes the projects have the debug and release libs have the same name! Consequently you'll get all sorts of linker errors. So far my success at building and linking against Bullet comes from: 1. Changing the build_*.bat scripts to use vs2015 rather than vs2010 (because ...
- Wed Oct 18, 2017 9:22 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Vs2015 Build failure - unicode problems
- Replies: 1
- Views: 5790
Vs2015 Build failure - unicode problems
I've download bullet3-2.87.zip ready to use it in a new project, run build_visual_studio_without_pybullet_vr.bat, open the build3/vs2010/0_Bullet3Solution.sln in Visual Studio 2015 (Update 3). If I just compile, I hit things like this: 10>..\..\examples\SharedMemory\b3PluginManager.cpp(117): error C...
- Thu Mar 23, 2017 11:50 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Mass not effecting dynamic rigid bodies?
- Replies: 8
- Views: 12873
Re: Mass not effecting dynamic rigid bodies?
If you want heavy objects to fall (accelerate) faster than light ones, you have to ask yourself why. The most likely answer is that the objects are affected by drag (air resistance) too - in which case rather than hacking gravity, it's probably better to add a drag force. This will give more realist...
- Tue Feb 21, 2017 11:06 pm
- Forum: Release Announcements
- Topic: Bullet 2.83 released on github: Example Browser, URDF
- Replies: 8
- Views: 118760
Re: Bullet 2.83 released on github
The feature to include the gyro terms in the solver is excellent - it turns out to be really important for correct simulation of aircraft spins and snap rolls etc, so much appreciated. I'll post a video of it in my R/C flight sim shortly. Thanks - Danny Have you posted your video already? If yes, w...
- Thu Feb 09, 2017 4:04 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Fixing "Hopping" - Rolling Sphere Collision
- Replies: 4
- Views: 7133
Re: Fixing "Hopping" - Rolling Sphere Collision
This can (will) happen if the ball hits internal edges in the surface it's rolling on. Difficult to tell from the video if that's the case as we'd need to see the collision shapes. Certainly if you have two boxes, A and B, next to each other with their top surfaces in the same plane, then as a ball ...
- Wed Sep 21, 2016 3:43 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Table Robot Legs Positions
- Replies: 5
- Views: 8384
Re: Table Robot Legs Positions
Bullet uses an iterative solver, so the degree to which it converges depends on the timestep and the number of solver iterations. Decreasing the former and increasing the latter normally helps. You could also look at the btMultiBody object, which implements a Featherstone solver. I'm not sure if tha...
- Wed Sep 21, 2016 3:27 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btHeightfieldTerrainShape going nuts
- Replies: 8
- Views: 28899
Re: btHeightfieldTerrainShape going nuts
Could they be hitting the internal edges? This can happen even if the terrain is completely flat, due to the way that the collision checks are done against the individual triangles. This started causing big problems for me, after putting up with it for a long time. You can see the problem here: http...
- Wed Aug 17, 2016 11:35 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: SoftBody behaviour with time increment and iteration number
- Replies: 3
- Views: 8543
Re: SoftBody behaviour with time increment and iteration num
Hi all, However, I found out that soft body (not even ropes, but patches) behave strangely with time step and iteration! Yes, I get this - my simulation timestep can vary a lot, and that causes problems because the accuracy of the rope simulation varies. I don't mind a bit of stretching (actually f...
- Sat Mar 19, 2016 10:19 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Directional Friction
- Replies: 5
- Views: 8456
Re: Directional Friction
What's wrong with the btCollisionObject::setAnisotropicFriction function?!
- Sat Feb 13, 2016 11:08 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Lightweight engine for simulating dice?
- Replies: 4
- Views: 13708
Re: Lightweight engine for simulating dice?
If you only want one die, on a plane for the floor, and a couple of planes for the walls, you can "roll your own" (ha ha - sorry!) using the verlet stick-and-particle method (though getting decent friction is always a pain with that). If you want any more than that, using Bullet (what plat...
- Mon Jan 04, 2016 8:33 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Friction: what is the unit?
- Replies: 5
- Views: 12308
Re: Friction: what is the unit?
Friction has no unit of measure; it is a dimensionless coefficient . Just think of it as a dial that twist from 0 (frictionless) to 1 (max friction). It is indeed dimensionless, but there's no upper limit. The friction value that you set on a rigid body object in Bullet isn't a "real" phy...