Hair instability with collision #59742

New Issue

Alexander Court · 2018-12-22T02:24:45+01:00

Alexander Court commented

2018-12-22 02:24:45 +01:00

System Information
Operating system: Windows 10
Graphics card: Geforce GTX 1070

Blender Version
Broken: 82c3fdd559

Short description of error
If dynamic hair comes in contact with collision object, the hair "explodes."

Exact steps for others to reproduce the error

Open attached file.
Bake hair simulation of cube.
Hair explodes as soon as it contacts suzanne.

Reproduced this with several emitter / collider meshes, particle settings etc.

hair_collision_bug.blend

system-info.txt

**System Information** Operating system: Windows 10 Graphics card: Geforce GTX 1070 **Blender Version** Broken: 82c3fdd559b32d88881883b99cf441935401cf05 **Short description of error** If dynamic hair comes in contact with collision object, the hair "explodes." **Exact steps for others to reproduce the error** 1. Open attached file. 2. Bake hair simulation of cube. 3. Hair explodes as soon as it contacts suzanne. - Reproduced this with several emitter / collider meshes, particle settings etc. [hair_collision_bug.blend](https://archive.blender.org/developer/F6030503/hair_collision_bug.blend) [system-info.txt](https://archive.blender.org/developer/F6030502/system-info.txt)

Alexander Court commented

2018-12-22 02:24:45 +01:00

Added subscriber: @spiegelball

blender-admin commented

2018-12-22 02:24:45 +01:00

#65708 was marked as duplicate of this issue

blender-admin commented

2018-12-22 02:24:45 +01:00

#63502 was marked as duplicate of this issue

Sebastian Parborg commented

2019-01-24 11:54:57 +01:00

Added subscribers: @brecht, @ZedDB

Sebastian Parborg commented

2019-01-24 11:54:57 +01:00

Hair collisions never really worked in the first place. See this example (the left one is the current blender hair physics): https://vimeo.com/200554110

IIRC there are plans to rewrite the particle/hair system. Hopefully problems like these will be solved then.

@brecht should we archive this or leave it as confirmed?

Hair collisions never really worked in the first place. See this example (the left one is the current blender hair physics): https://vimeo.com/200554110 IIRC there are plans to rewrite the particle/hair system. Hopefully problems like these will be solved then. @brecht should we archive this or leave it as confirmed?

Sebastian Parborg commented

2019-01-28 10:14:44 +01:00

Added subscriber: @Sergey

Sebastian Parborg commented

2019-01-28 10:14:44 +01:00

@Sergey any input?

Sergey Sharybin was assigned by Sebastian Parborg

2019-04-12 18:11:51 +02:00

Sebastian Parborg commented

2019-04-12 18:12:12 +02:00

Added subscribers: @EvertonSchneider, @nacioss

Sergey Sharybin was unassigned by Brecht Van Lommel

2019-04-12 20:01:44 +02:00

Brecht Van Lommel commented

2019-04-12 20:02:11 +02:00

This system has no maintainer currently, so marked as low priority without assignee.

Sebastian Parborg commented

2019-06-17 14:17:53 +02:00

Added subscribers: @iclone, @juang3d, @grosgood, @tomjk

AB commented

2019-07-25 00:22:05 +02:00

Added subscribers: @sebastian-4, @A-B

AB commented

2019-07-25 00:22:05 +02:00

@sebastian-4 Parborg (zeddb) Any updates on the particle/hair system rewrite? Are there any ways I can keep track of its progress?

Thanks

@sebastian-4 Parborg (zeddb) Any updates on the particle/hair system rewrite? Are there any ways I can keep track of its progress? Thanks

Sebastian Parborg commented

2019-07-25 10:55:45 +02:00

Not really, you can see the progress here: https://git.blender.org/gitweb/gitweb.cgi/blender.git/shortlog/refs/heads/functions

Philipp Oeser commented

2019-09-04 14:55:36 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2019-09-04 14:55:36 +02:00

Going over hair issues atm (to clear the tracker -- but also to have some input on what the next system has to take care of)

Note that this (explosion) only happens if the Hair Dynamics > Quality Steps are above 1.
There is a (newer) report open just for that, see #65038 (Hair Dynamics: Hair quality steps more than 1 results in increased collision reaction [like a multiplier])
I afaics, this was not the case in 2.79.
Not too familiar with the hair system, but maybe @juang3d can comment if he thinks this is a bug (I think it is)? (have a look at #65038)

Going over hair issues atm (to clear the tracker -- but also to have some input on what the next system has to take care of) Note that this (explosion) only happens if the `Hair Dynamics` > `Quality Steps` are above 1. There is a (newer) report open just for that, see #65038 (Hair Dynamics: Hair quality steps more than 1 results in increased collision reaction [like a multiplier]) I afaics, this was not the case in 2.79. Not too familiar with the hair system, but maybe @juang3d can comment if he thinks this is a bug (I think it is)? (have a look at #65038)

Juan Gea commented

2019-09-04 16:09:31 +02:00

Added subscriber: @LucaRood-3

Juan Gea commented

2019-09-04 16:09:31 +02:00

I will check #65038.

In any case Hair collission is flawed because it tries to do tri-tri intersections instead of edge-tri intersection, I spoke about this with @LucaRood-3 about this and he gave me clues on how to fix this, I am not experienced with this at all, but I¡ll try to solve it as soon as I can.

But maybe the #65038 is a different problem because hair quality steps more than 1 should result in better result, not in explosion

I will check #65038. In any case Hair collission is flawed because it tries to do tri-tri intersections instead of edge-tri intersection, I spoke about this with @LucaRood-3 about this and he gave me clues on how to fix this, I am not experienced with this at all, but I¡ll try to solve it as soon as I can. But maybe the #65038 is a different problem because hair quality steps more than 1 should result in better result, not in explosion

blender-admin commented

2019-09-04 19:33:26 +02:00

This issue was referenced by e52ad1835a

This issue was referenced by e52ad1835a6aaefab389b173728b9bb7ef2e754a

Philipp Oeser commented

2019-09-04 21:10:41 +02:00

Changed status from 'Open' to: 'Resolved'

Philipp Oeser closed this issue

2019-09-04 21:10:41 +02:00

Philipp Oeser self-assigned this 2019-09-04 21:10:41 +02:00

MrP commented

2019-09-05 07:25:49 +02:00

Added subscriber: @thechode

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Hair instability with collision #59742