Self-collision cloth causing unrealistic physics #54521

New Issue

Vinicius Fagundes · 2018-04-04T13:05:05+02:00

Vinicius Fagundes commented

2018-04-04 13:05:05 +02:00

System Information
Operating system and graphics card
Ubuntuy 17.10
AMD HD 5570{F2596406}

Blender Version
Broken: 2.79 (example: 2.69.7 4b206af, see splash screen)
Worked: (optional)

Short description of error
Cloth self-collision is causing unpredictable effects on the physics of the cloth on some meshes. For some reason, a cylinder with the top and bottom faces removed, it works fine, but when a face is removed to create a gap, it fails to work. Cloth self-collision works on a simple plane. When pinning is disabled, the problems get even more obvious.

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Play the physics animation (Alt-A)
On the left is a simple cloak. In the middle is the above mentioned cylinder with a gap, and on the right is a cylinder without a gap.
With pinning, the faulty cloths appear to be being stretched by something, and becomes more pronounced when pinning is disabled.

**System Information** Operating system and graphics card Ubuntuy 17.10 AMD HD 5570{[F2596406](https://archive.blender.org/developer/F2596406/TestScene.blend)} **Blender Version** Broken: 2.79 (example: 2.69.7 4b206af, see splash screen) Worked: (optional) **Short description of error** Cloth self-collision is causing unpredictable effects on the physics of the cloth on some meshes. For some reason, a cylinder with the top and bottom faces removed, it works fine, but when a face is removed to create a gap, it fails to work. Cloth self-collision works on a simple plane. When pinning is disabled, the problems get even more obvious. **Exact steps for others to reproduce the error** Based on a (as simple as possible) attached .blend file with minimum amount of steps Play the physics animation (Alt-A) On the left is a simple cloak. In the middle is the above mentioned cylinder with a gap, and on the right is a cylinder without a gap. With pinning, the faulty cloths appear to be being stretched by something, and becomes more pronounced when pinning is disabled.

Vinicius Fagundes commented

2018-04-04 13:05:05 +02:00

Added subscriber: @vinf100

Philipp Oeser commented

2018-04-04 13:57:01 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2018-04-04 13:57:01 +02:00

could you please upload your example file, so we can have a look?

Marking as incomplete for now...

could you please upload your example file, so we can have a look? Marking as incomplete for now...

Vinicius Fagundes commented

2018-04-04 14:04:31 +02:00

I did, it is beside my graphics card version on the link "F2596406". I know, that's a weird place, I don't know why it's there. I just drag and dropped it.

I did, it is beside my graphics card version on the link "[F2596406](https://archive.blender.org/developer/F2596406/TestScene.blend)". I know, that's a weird place, I don't know why it's there. I just drag and dropped it.

Philipp Oeser commented

2018-04-04 14:07:46 +02:00

Ah, sorry, having a look now...

Philipp Oeser commented

2018-04-04 14:30:34 +02:00

Changed status from 'Open' to: 'Archived'

Philipp Oeser closed this issue

2018-04-04 14:30:34 +02:00

Philipp Oeser self-assigned this 2018-04-04 14:30:34 +02:00

Philipp Oeser commented

2018-04-04 14:30:34 +02:00

Your objects geometries have very long/thin faces which makes it harder/impossible for the simulation to end up being somewhat realistic (lack of edges to bend at).
So without going into details (you should be able to find plenty of tutorials online), you should already end up with something more pleasing by just adding a couple of edgeloops in your file like here:
TestScene_more_subdivisions.blend

In summary I cant find a bug in the simulator here, closing...

Your objects geometries have very long/thin faces which makes it harder/impossible for the simulation to end up being somewhat realistic (lack of edges to bend at). So without going into details (you should be able to find plenty of tutorials online), you should already end up with something more pleasing by just adding a couple of edgeloops in your file like here: [TestScene_more_subdivisions.blend](https://archive.blender.org/developer/F2597034/TestScene_more_subdivisions.blend) In summary I cant find a bug in the simulator here, closing...

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Self-collision cloth causing unrealistic physics #54521