Search found 192 matches
- Sun Jan 19, 2020 7:25 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Getting Stuck issues with convexSweepTest
- Replies: 0
- Views: 1137
Getting Stuck issues with convexSweepTest
I'm reading things up for a release soon and one problem started to show up when I used convexSweepTest instead if my own collision tests. This is for kinematic collision hence no physics involved (think human actor movement). If actors hit a wall bullet runs into a getting-stuck situation. The firs...
- Thu Jul 27, 2017 8:21 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Generic6DOF joint friction bugged (with example)
- Replies: 5
- Views: 3126
Re: Generic6DOF joint friction bugged (with example)
I've setup another example with the kinematic joint friction case. Bullet is definitely bugged since it is unable to counter gravity using a motor even if the force is set ridiculously high. The atteched example shows the problem. If nobody is going to take a look at this problem I'm going to throw ...
- Mon Jul 24, 2017 2:34 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Generic6DOF joint friction bugged (with example)
- Replies: 5
- Views: 3126
Re: Generic6DOF constraint cancel force problem
I tried putting together a test case in ExampleBrowser (getting this to work is a real pain). The attached file is the first part of the problem, the one with the constraint doing strange things right at the start. In my real test case this also leads to strange jittering but I could not directly re...
- Thu Jul 20, 2017 10:49 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Generic6DOF joint friction bugged (with example)
- Replies: 5
- Views: 3126
Re: Generic6DOF constraint cancel force problem
I did some more testings and after running into a strange problem where the first step produces a linear velocity that should not be there I have the suspicion Bullet is bugged. Can somebody confirm this behavior to be wrong? // before doing simulation step (showing state after last simulation step)...
- Tue Jul 18, 2017 5:16 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Generic6DOF joint friction bugged (with example)
- Replies: 5
- Views: 3126
Re: Generic6DOF constraint cancel force problem
That's not the final goal. This is just a step in between to get it working. What I want in the end is inner joint friction, hence the joint resisting to be moved along the limited degree of freedom, like a rusty hinge on a door.
- Sun Jul 16, 2017 10:37 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Generic6DOF joint friction bugged (with example)
- Replies: 5
- Views: 3126
Generic6DOF joint friction bugged (with example)
I try to setup a linear motor on a generic 6dof constraint subclass with the simple task of cancelling all forces to keep a platform (no angular movement, only linear up-down movement possible) at a steady altitude. It's a preparation for more but I can't even get this simple problem working. I do t...
- Tue Dec 02, 2014 5:31 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btDbvtBroadphase very slow on sweep/ray testing
- Replies: 6
- Views: 4617
Re: btDbvtBroadphase very slow on sweep/ray testing
The optimization on the height terrain testing itself I can't share since it ties directly into my engine code and objects. The missing call-in point though can be patched with the patch file. It affects ray casts and convex casts but not the calls inside btCollisionWorld physics simulation due to t...
- Mon Dec 01, 2014 6:01 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btDbvtBroadphase very slow on sweep/ray testing
- Replies: 6
- Views: 4617
Re: btDbvtBroadphase very slow on sweep/ray testing
It sounds like a serious bug. There is an issue tracker here: https://github.com/bulletphysics/bullet3/issues If I'm not mistaken this bug tracker is for bullet v3 but this problem affects bullet v2. That said I've tracked down the problem to btHeightTerrain. It's testing every single triangle in t...
- Fri Nov 28, 2014 11:20 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btDbvtBroadphase very slow on sweep/ray testing
- Replies: 6
- Views: 4617
btDbvtBroadphase very slow on sweep/ray testing
The implementation of btDbvtBroadphase seems to have a serious performance issue. To see the problem create a simple work with btDbvtBroadphase. Add a few objects in it. Now try to make a convexSweepTest with a small sphere (for example 0.01 radius for example) or a rayHits test with a distance vect...
- Sun Nov 23, 2014 12:28 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Joint constraint friction
- Replies: 11
- Views: 6760
Re: Joint constraint friction
What I find in the source is this: btScalar mot_fact = getMotorFactor( limot->m_currentPosition, limot->m_loLimit, limot->m_hiLimit, tag_vel, info->fps * limot->m_stopERP); info->m_constraintError[srow] += mot_fact * limot->m_targetVelocity; info->m_lowerLimit[srow] = -limot->m_maxMotorForce; info-...
- Sat Nov 22, 2014 3:52 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Joint constraint friction
- Replies: 11
- Views: 6760
Re: Joint constraint friction
What I find in the source is this: btScalar mot_fact = getMotorFactor( limot->m_currentPosition, limot->m_loLimit, limot->m_hiLimit, tag_vel, info->fps * limot->m_stopERP); info->m_constraintError[srow] += mot_fact * limot->m_targetVelocity; info->m_lowerLimit[srow] = -limot->m_maxMotorForce; info->...
- Sat Nov 22, 2014 10:56 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Joint constraint friction
- Replies: 11
- Views: 6760
Re: Joint constraint friction
What exactly is the meaning of the max torque? Is it like target velocity? Constraints are basically optimization problems where you seek the minimum force needed to keep a desired velocity. If you can hit 0 velocity with less than your maximum friction force, it'll use less force than the max, but...
- Fri Nov 21, 2014 4:37 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Joint constraint friction
- Replies: 11
- Views: 6760
Re: Joint constraint friction
In this case just inner friction of a joint. I've looked at the topic but it uses motors and only 6dof has motors as far as I get it. btHingeConstraint and Hinge2Constraint also have them, just use enableAngularMotor with 0 target velocity and max torque being equal to max friction What exactly is ...
- Thu Nov 20, 2014 9:06 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Y-Axis bug in 6Dof
- Replies: 0
- Views: 2495
Y-Axis bug in 6Dof
I would like to see if somebody else has this bug in 2.82 . I take a simple door object, a box of something like size=(0.1, 2, 1.2) at (0,1,0) with a 6Dof constraint attached to the fixed body at (0,0,0) with 0 gravity. Now the following happens (angles always converted to radians). 1) x-axis range ...
- Thu Nov 20, 2014 5:48 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Joint constraint friction
- Replies: 11
- Views: 6760
Re: Joint constraint friction
In this case just inner friction of a joint. I've looked at the topic but it uses motors and only 6dof has motors as far as I get it.