Search found 4221 matches
- Sat Mar 09, 2019 1:13 am
- Forum: PyBullet Support and Feedback
- Topic: PyBullet and ROS?
- Replies: 2
- Views: 35237
Re: PyBullet and ROS?
It should be reasonably easy to write a bridge between ROS and PyBullet, for example in Python. PyBullet can already load URDF and SDF files and you can get all information and control through Python. Python can communicate to a PyBullet simulator and share ROS topics. There is no out-of-the box sol...
- Thu Mar 07, 2019 4:15 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Friction problem - Sphere isnt rolling on a straight line.
- Replies: 8
- Views: 11150
Re: Friction problem - Sphere isnt rolling on a straight line.
@Steven: Rolling friction works fine now, as long as you use btMultiBody, since we clamp against an implicit cone now, not against a pyramid. The fix is here: https://github.com/bulletphysics/bullet3/blob/master/src/BulletDynamics/Featherstone/btMultiBodyConstraintSolver.cpp#L116 The fix hasn't been...
- Mon Mar 04, 2019 1:15 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Friction problem - Sphere isnt rolling on a straight line.
- Replies: 8
- Views: 11150
Re: Friction problem - Sphere isnt rolling on a straight line.
OK, I got around implementing cone friction for rolling friction, so the two rolling friction directions are coupled and clamped against the friction cone together (instead of each rolling friction direction clamped against a friction pyramid).
https://github.com/bulletphysics/bullet3/pull/2138
https://github.com/bulletphysics/bullet3/pull/2138
- Fri Mar 01, 2019 4:22 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Friction problem - Sphere isnt rolling on a straight line.
- Replies: 8
- Views: 11150
Re: Friction problem - Sphere isnt rolling on a straight line.
Rolling friction indeed has an issue. We need to use cone friction for rolling friction (as we do for lateral friction). Will be fixed in a little while, see this issue: https://github.com/bulletphysics/bullet3/issues/2117 For now, disable rolling friction and manually apply some force (or use dampi...
- Wed Feb 27, 2019 6:06 pm
- Forum: PyBullet Support and Feedback
- Topic: Spherical Joints
- Replies: 10
- Views: 26235
Re: Spherical Joints
This PR exposes the torques: https://github.com/bulletphysics/bullet3/pull/2130 Thanks for the report! By the way, the DeepMimic humanoid can be trained using stable PD control now: https://www.youtube.com/watch?v=aiWxIjtMMFI When switching to spherical joint motors, the policy doesn't train. See th...
- Wed Feb 27, 2019 4:22 pm
- Forum: PyBullet Support and Feedback
- Topic: Pybullet not rendering correctly
- Replies: 9
- Views: 12997
Re: Pybullet not rendering correctly
This is likely some Intel OpenGL driver issue
~~~~~~
Version = 3.3 INTEL-10.4.14
Vendor = Intel Inc.
Renderer = Intel HD Graphics 3000 OpenGL Engine
~~~~~~~
~~~~~~
Version = 3.3 INTEL-10.4.14
Vendor = Intel Inc.
Renderer = Intel HD Graphics 3000 OpenGL Engine
~~~~~~~
- Wed Feb 27, 2019 4:19 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: Can i help Bullet to resolve collisions
- Replies: 2
- Views: 3629
Re: Can i help Bullet to resolve collisions
A few things to try: * use a smaller simulation step * increase the number of solver iterations * use a direct solver, Bullet provides Dantzig MLCP solver, see some of the examples in the ExampleBrowser * Use a btBoxShape for the ground * Enable SAT, separating axis test if you use btConvexHullShape...
- Tue Feb 26, 2019 12:52 am
- Forum: PyBullet Support and Feedback
- Topic: Remove Collision from an entire MultiBody
- Replies: 4
- Views: 8105
Re: Remove Collision from an entire MultiBody
Good to hear it is fixed!
- Tue Feb 26, 2019 12:52 am
- Forum: PyBullet Support and Feedback
- Topic: Spherical Joints
- Replies: 10
- Views: 26235
Re: Spherical Joints
Spherical joints still need a bit more work indeed. I'll add the getJointStateMultiDof for spherical joints soon. setJointMotorControlMultiDof indeed sets the maxForce. It is not misnamed: if you set a target velocity of 0, the joint motor can model joint friction given the maximum (friction) force....
- Tue Feb 26, 2019 12:44 am
- Forum: PyBullet Support and Feedback
- Topic: Pybullet not rendering correctly
- Replies: 9
- Views: 12997
Re: Pybullet not rendering correctly
Do the regular Bullet examples work? For example, what do you see if you run
~~~~~~~
python3 -m pybullet_envs.examples.testBike
~~~~~~~
(its implementation is testBike.py)
I see this, on Mojave 10.14.3:
When I run your script, it shows the R2D2 indeed, on the ground plane.
~~~~~~~
python3 -m pybullet_envs.examples.testBike
~~~~~~~
(its implementation is testBike.py)
I see this, on Mojave 10.14.3:
When I run your script, it shows the R2D2 indeed, on the ground plane.
- Fri Feb 22, 2019 7:45 pm
- Forum: PyBullet Support and Feedback
- Topic: Simulating closed loop structure in PyBullet
- Replies: 1
- Views: 5818
Re: Simulating closed loop structure in PyBullet
SDF and URDF files need to be tree structure/ open loop. PyBullet provides user constraints to close loops. See our Minitaur example how to add such constraint. https://github.com/bulletphysics/bullet3/blob/master/examples/pybullet/gym/pybullet_envs/minitaur/envs/minitaur.py#L391 See createConstrain...
- Tue Feb 19, 2019 12:18 am
- Forum: PyBullet Support and Feedback
- Topic: Remove Collision from an entire MultiBody
- Replies: 4
- Views: 8105
Re: Remove Collision from an entire MultiBody
PyBullet. setCollisionFilterGroupMask should be fixed in latest repository. Thanks for the report.
Note that link index -1 refers to the base, and link index >=0 refers to child links.
https://github.com/bulletphysics/bullet3/pull/2116
Note that link index -1 refers to the base, and link index >=0 refers to child links.
https://github.com/bulletphysics/bullet3/pull/2116
- Tue Feb 19, 2019 12:08 am
- Forum: PyBullet Support and Feedback
- Topic: Undesired behaviour when dropping cube
- Replies: 1
- Views: 3535
Re: Undesired behaviour when dropping cube
Yes, by default PyBullet adds some damping for stability. You can disable it like this: p.changeDynamics(boxId,-1,linearDamping=0, angularDamping=0) In addition, there is a maximum velocity of 100 units (m/s for linear velocity and radians/sec for angular velocity). If this is an issue, you can comp...
- Fri Feb 15, 2019 6:24 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btMultiBodyJointMotor interaction and control problem.
- Replies: 3
- Views: 4287
Re: btMultiBodyJointMotor interaction and control problem.
Can you please file an issue in the tracker, with a C++ reproduction case and/or PyBullet reproduction case (PyBullet is preferable).
https://github.com/bulletphysics/bullet3/issues
Thanks!
Erwin
https://github.com/bulletphysics/bullet3/issues
Thanks!
Erwin
- Mon Feb 11, 2019 4:52 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Is there SAT algorithm in Bullet Physics Engine
- Replies: 2
- Views: 4183
Re: Is there SAT algorithm in Bullet Physics Engine
Yes, Bullet provides a SAT implementation. You need to call the convexHull->initializePolyhedralFeatures(), this will create edges/trangles for a point cloud. convex hull generation is then enable SAT using getDispatchInfo().m_enableSatConvex=true; Implementation is in src\BulletCollision\CollisionD...