Geometry Nodes does not work with Rigid Body correctly #108144

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opened 2023-05-22 13:20:53 +02:00 by Josep-Jover · 5 comments

Josep-Jover commented

2023-05-22 13:20:53 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: Intel(R) UHD Graphics 630 Intel 4.5.0 - Build 26.20.100.7925

Blender Version
Broken: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: e1ccd9d4a1d3
Worked: (newest version of Blender that worked as expected)

Short description of error
I have seen that Geometry Nodes does not work with Rigid Body correctly.

Exact steps for others to reproduce the error
I join you and example with two flags and two dominoes pieces.
Bug Gemoetry Nodes and Rigid Body 1.blend

A flag traditionally rotates on the "Z" axis and pushes the domino piece.
The other flag uses the geometry nodes to rotate and instead of pushing the domino, it through it.

The Geometry Nodes only did a 'Transform Geometry' to rotate the flag.

I opened the issue on https://blender.stackexchange.com/ and no one could did it work.
I don't know if is a bug or that it still not deployed.

I hope this is helpful and that you can fix it.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: Intel(R) UHD Graphics 630 Intel 4.5.0 - Build 26.20.100.7925 **Blender Version** Broken: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: `e1ccd9d4a1d3` Worked: (newest version of Blender that worked as expected) **Short description of error** I have seen that Geometry Nodes does not work with Rigid Body correctly. **Exact steps for others to reproduce the error** I join you and example with two flags and two dominoes pieces. [Bug Gemoetry Nodes and Rigid Body 1.blend](/attachments/af4299d8-457f-4365-b9e1-a474497b8e4b) A flag traditionally rotates on the "Z" axis and pushes the domino piece. The other flag uses the geometry nodes to rotate and instead of pushing the domino, it through it. ![Captura 1.PNG](/attachments/27698b8d-c12d-4cbe-a301-6627b5c94b0a) The Geometry Nodes only did a 'Transform Geometry' to rotate the flag. I opened the issue on https://blender.stackexchange.com/ and no one could did it work. I don't know if is a bug or that it still not deployed. I hope this is helpful and that you can fix it.

Captura 2.PNG

64 KiB

Bug Gemoetry Nodes and Rigid Body 1.blend

1013 KiB

Captura 1.PNG

319 KiB

Captura 2.PNG

Josep-Jover added the

labels 2023-05-22 13:20:54 +02:00

Iliya Katushenock commented

2023-05-22 14:47:09 +02:00

Member

I really don't believe this can work with generating modifiers...

I really don't believe this can work with generating modifiers...

Iliya Katushenock added the

Nodes & Physics

labels 2023-05-22 15:00:39 +02:00

Josep-Jover commented

2023-05-22 22:09:13 +02:00

Author

Even if you rotate the flag directly with Geometry Nodes without using 'Modifiers' it still not working.

Even if you rotate the flag directly with Geometry Nodes without using 'Modifiers' it still not working.

Germano Cavalcante commented

2023-05-23 00:38:26 +02:00

Member

Thanks for the report. I can confirm the problem. Hopefully this will be resolved soon, but note that the rigid body system has no active developer working on it at the moment. Therefore, there is no guarantee that this issue will be resolved soon.

There are some seemingly related issues like:
#99867 (Rigid body doesn't work when collision is set to mesh, deform and deforming)

Thanks for the report. I can confirm the problem. Hopefully this will be resolved soon, but note that the rigid body system has no active developer working on it at the moment. Therefore, there is no guarantee that this issue will be resolved soon. There are some seemingly related issues like: #99867 (Rigid body doesn't work when collision is set to mesh, deform and deforming)

Germano Cavalcante added

Nodes & Physics

and removed

Nodes & Physics

labels 2023-05-23 00:39:05 +02:00

Josep-Jover commented

2023-05-23 09:58:59 +02:00

Author

Thanks for the reply. I hope it will resolved soon too.

Thanks for the reply. I hope it will resolved soon too.

Devon R commented

2023-11-18 22:54:21 +01:00

While this isn't a fix, if you're deforming (not generating) a mesh with geometry nodes, and you only care about generalized collisions, you can get an interaction with the rigid body world using vertex parenting.

Disable the realtime display on your geometry nodes modifier
Create a proxy mesh that can stand in for the shape of your collision and match it to the shape
In edit mode on your ORIGINAL mesh (the one with the geo nodes on it), select 3 representative vertices that closely match the motion you're trying to represent
Switch to object mode, then first select the proxy mesh, THEN the deformed mesh (so that the deformed/geo nodes mesh is the active object), then Ctrl+P to parent and select 'Vertex (Triangle)'
You can now enable the display on the geo nodes modifier, if it worked, the proxy should follow with it
On the proxy mesh, enable Rigid Body, set to Passive, check Animated, then set Collisions > Source to Final (may not be necessary)

If the proxy mesh follows the motion close enough when you scrub in the viewport, it should be suitable as a stand-in, and since it has no geo nodes on itself, the simulation handles it properly.

Obviously this won't work if the exact geometry of your collider mesh is important (like if you're making an, ocean wave, or something). But if you only care about the general shape and can afford to use convex hull this works for e.g. the example shown in the issue.

It should still be fixed in blender itself, obviously. But this works if you really need to make it work.

While this isn't a fix, if you're _deforming_ (not generating) a mesh with geometry nodes, and you only care about generalized collisions, you can get an interaction with the rigid body world using vertex parenting. 1. Disable the realtime display on your geometry nodes modifier 2. Create a proxy mesh that can stand in for the shape of your collision and match it to the shape 3. In edit mode on your ORIGINAL mesh (the one with the geo nodes on it), select 3 representative vertices that closely match the motion you're trying to represent 4. Switch to object mode, then first select the proxy mesh, THEN the deformed mesh (so that the deformed/geo nodes mesh is the active object), then Ctrl+P to parent and select 'Vertex (Triangle)' 5. You can now enable the display on the geo nodes modifier, if it worked, the proxy should follow with it 6. On the proxy mesh, enable Rigid Body, set to Passive, check Animated, then set Collisions > Source to Final (may not be necessary) If the proxy mesh follows the motion close enough when you scrub in the viewport, it should be suitable as a stand-in, and since it has no geo nodes on itself, the simulation handles it properly. Obviously this won't work if the exact geometry of your collider mesh is important (like if you're making an, ocean wave, or something). But if you only care about the general shape and can afford to use convex hull this works for e.g. the example shown in the issue. It should still be fixed in blender itself, obviously. But this works if you really need to make it work.

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