Real-Time Physics Simulation Forum

PyBullet Support and Feedback • Re: Soft body contact force

2025-03-17T10:18:29+00:00

For your case, I suggest adding a rigid sensor plate between the soft body and table,build now gg linked by a joint, and measure there.

Statistics: Posted by otis — Mon Mar 17, 2025 10:18 am

PyBullet Support and Feedback • Re: Replicate ai generated animation back in pybullet.

2025-03-17T10:16:47+00:00

To replicate AI-generated animations in PyBullet smoothly, ditch time.sleep() and sync playback to p.stepSimulation() with a fixed timestep like 1/240 Hz,Buckshot Roulette interpolating joint positions between keyframes for fluidity.

Statistics: Posted by otis — Mon Mar 17, 2025 10:16 am

PyBullet Support and Feedback • Re: Create Half Cylinder in PyBullet

2025-03-06T06:16:47+00:00

PyBullet’s `createCollisionShape` doesn’t directly support half cylinders, but you can create one by modeling it as a mesh in a tool like Blender,Block Blast exporting it as an `.obj` file, and loading it with `GEOM_MESH` in PyBullet.

Statistics: Posted by otis — Thu Mar 06, 2025 6:16 am

PyBullet Support and Feedback • Re: Spring pendulum creation

2025-03-04T09:12:03+00:00

Hello everyone. I'm rather new to pybullet and I was looking to create a simulation of a spring pendulum for a physics slope game project at school. What would be the best way to do this? Is there a spring preset in pybullet?

No, PyBullet does not have a specific spring preset designed explicitly for a spring pendulum. However, it provides the `btGeneric6DofSpring2Constraint`, which can simulate spring behavior between two rigid bodies.

Statistics: Posted by otis — Tue Mar 04, 2025 9:12 am

PyBullet Support and Feedback • Re: How to remove bodyA when its in contact with bodyB?

2023-12-20T09:36:13+00:00

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Statistics: Posted by RKaji — Wed Dec 20, 2023 9:36 am

PyBullet Support and Feedback • Re: Changing background color or texture?

2023-07-04T12:04:30+00:00

You can change the background color of the GUI in PyBullet using the p.configureDebugVisualizer() function.

You can specify the background color using the rgbBackground parameter. This function accepts multiple parameters other than rbgBackground parameter.

Here’s an example:

Code:

p.configureDebugVisualizer(rgbBackground=[0, 0, 0])

In this example, the rgbBackground parameter is used to set the background color to black. You can pass an RGB vector [red, green, blue] to set a color of your choice. Each color value should be between 0 and 1.

Statistics: Posted by nobuyuki — Tue Jul 04, 2023 12:04 pm

PyBullet Support and Feedback • PyBullet: Connect client to multiple physics servers via Shared Memory

2023-06-06T11:54:48+00:00

Hi there!

I'm trying to find a way to turn on/off gravity forces only for specific objects using pyBullet.

In the Quickstart Guide (page 87) it is said, that there might be a way by running a second physics server:

Question:
How to turn off gravity only for some parts of a robot (for example the arm)?

Answer:
At the moment this is not exposed, so you would need to either turn of gravity acceleration for all objects, and manually apply gravity for the objects that need it. Or you can actively compute gravity compensation forces, like happens on a real robot. Since Bullet has a full constraint system, it would be trivial to compute those anti-gravity forces: You could run a second simulation (PyBullet lets you connect to multiple physics servers) and position the robot under gravity, set joint position control to keep the position as desired, and gather those 'anti-gravity' forces. Then apply those in the main simulation.

As a first step i want to connect a client with two servers by using the SHARED_MEMORY mode.
However, I only managed it to connect my client with one server like this:

Server:

Code:

p.connect(p.GUI_SERVER)

Client:

Code:

p.connect(p.SHARED_MEMORY)

Now, I want to run a second server and connect to it via Shared Memory. In the documentation on page 5 it says, that I need to specify a key for each server:

in SHARED_MEMORY mode, optional shared memory key. When starting ExampleBrowser or SharedMemoryPhysics_* you can use optional command-line --shared_memory_key to set the key. This allows to run multiple servers on the same machine.

So how exactly do I have to implement this? Is there any example script which does exactly that?

I would be very grateful, if someone could point me in the right direction!

Thank you,
Christoph

Statistics: Posted by Yogha001 — Tue Jun 06, 2023 11:54 am

PyBullet Support and Feedback • Failure in loading XML that the error raises is related to URDF error?

2023-04-03T05:10:20+00:00

Hi. I'm trying to load my xml file which has no problem loading it in Mujoco.
However as tried in pybullet, it raised this error

b3Printf: b3Warning[examples/SharedMemory/PhysicsServerCommandProcessor.cpp,3584]:

b3Printf: URDF file with multiple root links found.

Even though not using URDF, why is this error raised, and how can it be fixed ?

Statistics: Posted by chankyo — Mon Apr 03, 2023 5:10 am

PyBullet Support and Feedback • How to create a elastic cylinder?

2023-03-26T10:19:22+00:00

Now, I can create a cylinder:

Code:

import pybullet as pphysicsClient = p.connect(p.GUI)p.setGravity(0,0,-10)plane_shape = p.createCollisionShape(p.GEOM_PLANE)plane_body = p.createMultiBody(baseCollisionShapeIndex=plane_shape)cylinder = p.createCollisionShape(p.GEOM_CYLINDER, radius=0.1, height=2)body = p.createMultiBody(baseMass=1, baseCollisionShapeIndex=cylinder,                          basePosition=[0, 0, 1], baseOrientation=[0, 0, 0, 1])force_magnitude = 100 end_pos = [0.9, 0, 1] p.applyExternalForce(body, -1, forceObj=[force_magnitude, 0, 0], posObj=end_pos, flags=p.WORLD_FRAME)import timefor i in range(10000):    p.stepSimulation()    time.sleep(1. / 240.)p.disconnect()

And, I expect the cylinder would turn tu be a arc when the force is add on the top of cylinder. Now, the cylinder is rigid. How can I make it to be elastic?

Any suggestion is appreciated~~~

Statistics: Posted by zhang_qiang — Sun Mar 26, 2023 10:19 am

PyBullet Support and Feedback • Re: objects not visible after a while

2023-03-14T17:27:08+00:00

I am having the same issue. Have you found a solution? I believe this has to do with memory leak / overflow of some sort.

Statistics: Posted by maurock — Tue Mar 14, 2023 5:27 pm