Blender 2.81 - Hair collisions explode hair particles #71047

New Issue

Pierre Schiller · 2019-10-23T19:11:44+02:00

Pierre Schiller commented

2019-10-23 19:11:44 +02:00

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX TITAN X/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 382.05

Blender Version
Broken: version: 2.81 (sub 15), branch: master, commit date: 2019-10-22 15:34, hash: ac18c3c28d
Worked: (optional)

Short description of error
If you set up a collision object (cylinder) to interact against hair, particles are blown away.

Exact steps for others to reproduce the error
Create a long cylinder to interact with hair. Go to property tabs, activate collision.
Create a Zuzzane. Select a vertex group to represent scalp. Create a particle system>hair. On the vertex groups properties from the hair particle tabs, select for density: Hair scalp vertex group. Edit hair particles, comb until you see the hair wig.
Activate "dynamics" on hair.
Animate cylinder to pass through hair.
Playback animation (watch it cache).
Kink hair particles (hair in general) explodes in contact with the collisioner.

ALSO: Caching for hair (seems) to be done internally. This simple file would´ve weighted only 4-5mb on blender 2.79. It weights 29Mb on Blender 2.81.

FILE: https://drive.google.com/open?id=1cd4jvcXMAo-Gark3lebcY1m8aGarLayv

**System Information** Operating system: Windows-7-6.1.7601-SP1 64 Bits Graphics card: GeForce GTX TITAN X/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 382.05 **Blender Version** Broken: version: 2.81 (sub 15), branch: master, commit date: 2019-10-22 15:34, hash: `ac18c3c28d` Worked: (optional) **Short description of error** If you set up a collision object (cylinder) to interact against hair, particles are blown away. **Exact steps for others to reproduce the error** Create a long cylinder to interact with hair. Go to property tabs, activate collision. Create a Zuzzane. Select a vertex group to represent scalp. Create a particle system>hair. On the vertex groups properties from the hair particle tabs, select for density: Hair scalp vertex group. Edit hair particles, comb until you see the hair wig. Activate "dynamics" on hair. Animate cylinder to pass through hair. Playback animation (watch it cache). Kink hair particles (hair in general) explodes in contact with the collisioner. ALSO: Caching for hair (seems) to be done internally. This simple file would´ve weighted only 4-5mb on blender 2.79. It weights 29Mb on Blender 2.81. FILE: https://drive.google.com/open?id=1cd4jvcXMAo-Gark3lebcY1m8aGarLayv

Pierre Schiller commented

2019-10-23 19:11:44 +02:00

Added subscriber: @PierreSchiller

Germano Cavalcante commented

2019-10-24 14:57:39 +02:00

Added subscribers: @LucaRood-3, @JacquesLucke, @mano-wii

Luca Rood was assigned by Germano Cavalcante

2019-10-24 14:57:39 +02:00

Germano Cavalcante commented

2019-10-24 14:57:39 +02:00

I can confirm.
I'm not sure when the hair collision was supported.
But I can see that it was already supported on blender 2.79 and that it worked better there.

There are plans to replace the particle system, but I don't know if this area will be touched (@JacquesLucke?).
@LucaRood-3, you've worked in this area before, would you be willing to take a look?

I can confirm. I'm not sure when the hair collision was supported. But I can see that it was already supported on blender 2.79 and that it worked better there. There are plans to replace the particle system, but I don't know if this area will be touched (@JacquesLucke?). @LucaRood-3, you've worked in this area before, would you be willing to take a look?

Philipp Oeser commented

2019-11-11 10:53:11 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2019-11-11 10:53:11 +01:00

Not sure why the hair doesnt seem to be simulating/moving at all prior to collision?
If I delete the Edit and comb again, everything seems to be working rather "normally".

(note I made a fix for hair collisions in e52ad1835a -- looks like this was only for the better though, cant see a direct relation here...)

Not sure why the hair doesnt seem to be simulating/moving at all prior to collision? If I delete the Edit and comb again, everything seems to be working rather "normally". (note I made a fix for hair collisions in e52ad1835a -- looks like this was only for the better though, cant see a direct relation here...)

Luca Rood was unassigned by Dalai Felinto

2019-12-23 13:46:04 +01:00

Germano Cavalcante commented

2020-01-10 16:29:31 +01:00

Changed status from 'Confirmed' to: 'Needs User Info'

Germano Cavalcante commented

2020-01-10 16:29:31 +01:00

I can reproduce the problem with the attached file, but not by creating a file from scratch.
I also tested with D6545, but the result was not much different.
Also if I edit the particles in the editor, the problem goes away.
So this seems to be a problem with the file. (Maybe it brought something in previous versions that broke in the current version).

The information about reproducing the problem from scratch needs to be updated.

I can reproduce the problem with the attached file, but not by creating a file from scratch. I also tested with [D6545](https://archive.blender.org/developer/D6545), but the result was not much different. Also if I edit the particles in the editor, the problem goes away. So this seems to be a problem with the file. (Maybe it brought something in previous versions that broke in the current version). The information about reproducing the problem from scratch needs to be updated.

Richard Antalik commented

2020-01-19 23:45:46 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-01-19 23:45:46 +01:00

Changed status from 'Needs User Info' to: 'Archived'

Richard Antalik closed this issue

2020-01-19 23:45:46 +01:00

Richard Antalik self-assigned this 2020-01-19 23:45:46 +01:00

Richard Antalik commented

2020-01-19 23:45:46 +01:00

Since last asking for information it has been 7 or more days, due to the policy of our bug tracker we will have to close the report

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Blender 2.81 - Hair collisions explode hair particles #71047