Search found 4064 matches

by Erwin Coumans
Wed Dec 13, 2017 2:18 am
Forum: PyBullet Support and Feedback
Topic: Problem when importing mesh as ground
Replies: 2
Views: 12

Re: Problem when importing mesh as ground

Use the flags=GEOM_FORCE_CONCAVE_TRIMESH in the createCollisionShape command.
by Erwin Coumans
Wed Dec 13, 2017 2:17 am
Forum: PyBullet Support and Feedback
Topic: how to change joint position
Replies: 2
Views: 16

Re: how to change joint position

The main way to create a robot is creating a URDF file. Aside from that, you can use createMultiBody. get the Bullet source code, and see Bullet/examples/pybullet/examples/createMultiBodyLinks.py for an example (this is in the Pybullet Quickstart Guide) The 'createConstraint' is only to attach multi...
by Erwin Coumans
Mon Dec 11, 2017 8:19 pm
Forum: PyBullet Support and Feedback
Topic: Built-in box visual object has incorrect normals, when created via loading a urdf
Replies: 4
Views: 24

Re: Built-in box visual object has incorrect normals, when created via loading a urdf

What is 'incorrect' about the normals? I get a similar image than you. What kind of normals would you expect? The built-in cube likely uses interpolated vertex normals, instead of face normals. If you want unique normals that point in the face direction,why don't you use Bullet/data/cube.obj? by the...
by Erwin Coumans
Mon Dec 11, 2017 7:35 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to transform a body as if it was attached to another body
Replies: 4
Views: 110

Re: How to transform a body as if it was attached to another body

what is making it move along with the board then? Gravity pulls the ball against the board, and friction makes the ball move the board. This works just fine in Bullet, and using pybullet and its VR physics server makes it really easy to create this exact scenario in your video. It is important that...
by Erwin Coumans
Mon Dec 11, 2017 7:32 pm
Forum: General Bullet Physics Support and Feedback
Topic: Collision response filtering
Replies: 3
Views: 41

Re: Collision response filtering

There is no such thing as one-way collision response, since Newton laws action force = - reaction force. It is not clear what you try to achieve, and why this requires a non-physical interaction. Usually you let the user control some object (sphere) using some constraint that follows the user intent...
by Erwin Coumans
Mon Dec 11, 2017 7:26 pm
Forum: PyBullet Support and Feedback
Topic: Questions about pybullet use in videogame
Replies: 4
Views: 457

Re: Questions about pybullet use in videogame

PyBullet uses Bullet C++ under the hood. As long as you don't use many python calls before/after each 'stepSimulation' performance should be the same. Note that PyBullet is configured for VR, robotics and RL by default, with a small timestep (1./240) and a large number of solver iterations (50) by d...
by Erwin Coumans
Mon Dec 11, 2017 7:23 pm
Forum: PyBullet Support and Feedback
Topic: some concepts
Replies: 2
Views: 27

Re: some concepts

In robotics and multibodies, bodies are often called a 'link'. In pybullet, there is the concept of 'bodyUniqueId' for a multibody. If the multibody has children, those children are called 'links'. You can access all the links of a multibody through a link index, starting from 0 to the number of lin...
by Erwin Coumans
Mon Dec 11, 2017 7:18 pm
Forum: PyBullet Support and Feedback
Topic: Built-in box visual object has incorrect normals, when created via loading a urdf
Replies: 4
Views: 24

Re: Built-in box visual object has incorrect normals, when created via loading a urdf

It is not clear what the problem is. Can you share a simple pybullet Pythons script that shows the problem?
by Erwin Coumans
Sun Dec 10, 2017 12:18 am
Forum: General Bullet Physics Support and Feedback
Topic: collision detection problem of collision shape controlled by haptic device
Replies: 3
Views: 93

Re: collision detection problem of collision shape controlled by haptic device

Have you played with all the SoftBody demos in the Bullet ExampleBrowser? Various demos show rigid bodies resting on soft bodies, with two-way interaction. btRigidBody uses impulse-based (velocity-level) dynamics btSoftBody uses position based dynamics. There is two-way interaction between btSoftBod...
by Erwin Coumans
Sun Dec 10, 2017 12:16 am
Forum: General Bullet Physics Support and Feedback
Topic: How to transform a body as if it was attached to another body
Replies: 4
Views: 110

Re: How to transform a body as if it was attached to another body

You should use a constraint to move the board, instead of directly setting its position (and/or velocity). BodyA of the constraint is the board, bodyB is some fixed object. Then you configure the constraint transforms to sync to some transform. This is how it is done in the Bullet VR examples using ...
by Erwin Coumans
Fri Dec 08, 2017 3:08 pm
Forum: General Bullet Physics Support and Feedback
Topic: pybullet: Synthetic Cameras default to open. Is there a way to change this behavior?
Replies: 2
Views: 69

Re: pybullet: Synthetic Cameras default to open. Is there a way to change this behavior?

Can you try the COV_ENABLE_RGB_BUFFER_PREVIEW, COV_ENABLE_DEPTH_BUFFER_PREVIEW, COV_ENABLE_SEGMENTATION_MARK_PREVIEW flags
in configureDebugVisualizer?

enable = 0 or 1

Code: Select all

pybullet.configureDebugVisualizer(pybullet.COV_ENABLE_RGB_BUFFER_PREVIEW,enable)
by Erwin Coumans
Thu Dec 07, 2017 7:07 am
Forum: PyBullet Support and Feedback
Topic: UR3 COLLADA DAE mesh conversion issue
Replies: 1
Views: 42

Re: Pybullet Quickstart Guide and other resources

It is likely some up-axis (Y versus Z) issue with COLLADA DAE files. Try rotating them around the x-axis for 90 degrees (+ or -), when converting them to OBJ. If you share the URL to the UR3 with DAE files, someone may be able to help. Please submit a new issue next time (don't reply with a new issu...
by Erwin Coumans
Wed Dec 06, 2017 3:28 pm
Forum: PyBullet Support and Feedback
Topic: Pybullet Quickstart Guide and other resources
Replies: 0
Views: 68

Pybullet Quickstart Guide and other resources

You can find the PyBullet Quickstart Guide at http://pybullet.org with an introduction and documentation about the PyBullet API. Installation of PyBullet should be as easy as pip install pybullet Various reinforcement learning environments are implemented in PyBullet, using the OpenAI Gym interface....
by Erwin Coumans
Wed Dec 06, 2017 3:22 pm
Forum: PyBullet Support and Feedback
Topic: how much time for train kuka grasping?
Replies: 2
Views: 462

Re: how much time for train kuka grasping?

The kuka grasping environment had some issues that we resolved. In addition, it is a very sparse reward (at the end) which slows down RL training a lot. Using evolution stategies (ESTool) we can get some meaningful results. See also this post with details: http://blog.otoro.net/2017/11/12/evolving-s...
by Erwin Coumans
Wed Dec 06, 2017 3:17 pm
Forum: PyBullet Support and Feedback
Topic: Questions about pybullet use in videogame
Replies: 4
Views: 457

Re: Questions about pybullet use in videogame

Hi, long time lurker and first time poster :) Welcome! I have a few questions regarding pybullet and how it can be used with the recent C# bindings that make it possible to connect to a Bullet server within the Unity3d game engine, makes for interesting possibilities! 1) If we wanted to simulate co...