Isaac Sim Version
5.0.0
Operating System
Other (please specify): Ubuntu 24.04
GPU Information
- Model: NVIDIA GeForce RTX 4060
- Driver Version: 570.169
Topic Description
Detailed Description
(Describe the issue in detail, including what you were trying to do, what you expected to happen, and what actually happened)
Steps to Reproduce
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I want to control the barrel as shown in the figure below
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The cylinder is a fixed point with gravity disabled and the barrel is body1 connected via revolute joint
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For my MSc Dissertation I need to set the angle and multiple fix angles like 0, 5, 10 , 15, 20 degrees and analyse the flow of the cube behaviour with it.
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I have attached the screenshots to show the process, and I want an easy way to control this barrel tilt based on command
Screenshots or Videos
Additional Information
What I’ve Tried
I have tried Python script with this a code to increment angle with a loop. It works but not correctly. For example an angle of 25 deg in code will only generate a real tilt of 19 degrees along the Y axis
I also teies action graph and the articulation controller for position control, but in documentation it is only given for velocity control and the system glitches when I try position controll
Please, do me in fixing this issue
@gokulsaseendran Have you looked into the action graph node write prim attribute? Maybe you can use this node to write the orientation of the barrel to tilt.
Or if you prefer to do it via script, here is an example script to rotate a cylinder for your reference.
test.py (4.6 KB)
The python script did do a good job and I had done the tilt using the python script before as well and it was working. The main issue was with integrating omigraph
Also, once the tilt in done the materials I simulated are glitching and some of them seeping through the conveyor even though I enabled rigid bodies to both. Also, the cube seems like rotating around the cylinder like in a washing machine, which was not enabled as well. I locked the cylinder axes and only enable y axis for pitching motion. Why would this be happening in this case? Is it something I need to consider? I got the cylinder from Isaac assets which was a beaker and I changed the material properties. I wanted to bake a cylinder myself but it seems impossible in isaac sim. I think I might need to import cad file from fusion 360 and upload it, but still not very sure.
I have attached the video to show as reference as well. Please let me know how to fix it as I need to find an optimal angle for my tilt as part of my dissertation as well.
i will also attach the zip file for the USD for the same from Isaac sim 5.0.0.
cube_test_withnew_cylinder.zip (26.0 KB)
will you be able to run this file and see?
Thanks for your file. I can see that the cubes are going through the barrel even though you have collision preset for the cubes. Somehow I am not able to add collision preset for the barrel.
Let me reach out to the internal team.
Hi @gokulsaseendran I confirmed with the internal team that this is a bug. The physics somehow doesn’t work well with GPU.
As a workaround, you can click on PhysicsScene. In the property tab, under Physics, uncheck Enable GPU Dynamics and then select MBP for Broadphase Type. That would fix this issue.
Hi @zhengwang
Thank you very much for your prompt reply. I will try this approach. But also as a walk around his can we design a hollow cylinder in Isaac Sim 5.0.0, and I could only build a solid one in it. I could also a use a a hollow cylinder with similar dimension.
I tried my importing a usdc file of a cylinder designed in Fusion 360 and it has been glitching the interface. How could we design a custom object in Isaac Sim, because I’ve scene researchers make a complete new environment with objects like the kitchen and all equipments. Can you let me know what is the best method to model my simulated nuclear environment?
Hi @gokulsaseendran! I suggest you ask this question in the omniverse forum Omniverse - NVIDIA Developer Forums
Here are also youtube tutorial videos about how to model assets, for example, this one.
Hi @zhengwang , I did try unchecking “Enable GPU Dynamics” and selected MBP. Though it did solve problem of the cubes seeping through the cylinder, it is causing issue with the control of the revolute joint. The revolute joint can’t be controlled like I used to before and it is getting stuck at a point like being rigid. How do you think I could enable a quick fix to control the joint in this case, where GPU is unchecked?
@gokulsaseendran could you please share your USD with the action graph or script that tilts the barrel? The one you shared earlier has an empty action graph.
@zhengwang I am attaching the script file for tilting the joint and the USD together with this message as a zip file. Please, do run the program and check it out. If not please, do share a code which could work for the same.
Barrel tilting USD and code.zip (29.5 KB)
If not revolute joint, it would be great if you could integrate a UR5 robot URDF file into it with a gripper attached to barrel. The, give a guide to use MoveIt to control the robot.
This is how the hardware looks like with the simulated waste materials 3D printed and the 3D printed attachment
I had a severe learning curve in integrating this initially for my dissertation and there were issues with connecting the robot to Isaac ROS bridge and open the MoveIt interface.
Because my actual hardware experiment is based on a UR5 robot and conveyor system. I was using a revolute joint to make the process easier and the main focus was on tilt.
Please, do let me know what could be a viable solution for this case.
Hi @gokulsaseendran thanks for your files!
Actually you only need to move your barrel and joint_attachment up a little bit. In your original USD file, your barrel got stuck with the stick from the conveyor when it is tilting down.
I moved both of them up (including the cubes and it works fine!
HI @zhengwang ,
This partial tilt did work for me, but it is not going beyond a particular value. I will show a video of it without the conveyor in the setup
I am manually adjusting the “target position” value using the slider in Property panel, upto 80 degrees. But the orientation of the barrel is barely going beyond 10 degree around y axis. This was the issue I had been facing. It is tilting beyond a point.
I am attaching the zip file to this USD as a well in this thread.
Angle_set_varying_restitution.zip (27.1 KB)
Hi @zhengwang, it would actually be really great if you could organise a quick teams meeting to discuss on this and fix this live during the call.
Sorry to get back to you late and thanks for the USD file you shared.
I am able to replicate this issue. I found that if I move the joint_attachment higher, the barrel is able to tilt more. The target position value in the property doesn’t really control the tilting of the barrel. I am not sure how these two are related.
Let me get back to the internal team about this.
Thank you very much for checking it out, and do let me know what the problem is, in this scenario.
It seems to me that this bug is related to a previously reported one and our recommendation there is not to have a PxRigidDynamic being over constrained, that is just to leave the angular constraint on the joint, but to remove the same angular constraint from the PxRigidDynamic.
I have added a screen shot of where the PxRigidDynamic constraints are removed. This is the desired configuration.
@gokulsaseendran let us know if the suggested fix by @pdeherasciec solves the issue
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