Adding Blender hair bug #38928

New Issue

johan tri handoyo · 2014-03-03T06:14:02+01:00

johan tri handoyo commented

2014-03-03 06:14:02 +01:00

System Information
Ubuntu 12.04 64bit, NVIDIA GTX 650 Ti

Blender Version
Broken: Blender 2.69.11
Worked: (optional)

I was trying to add hair in particle edit mode. But the hair was not added on the assigned surface. It's just a mess and the hair scattered all over the place. I try a combination of modifier arrangement and the "use modifier stack" button. But the result was not satisfactory.

Please see the attachment for screen capture and .blend file example.
biru.blend

Thank you

**System Information** Ubuntu 12.04 64bit, NVIDIA GTX 650 Ti **Blender Version** Broken: Blender 2.69.11 Worked: (optional) I was trying to add hair in particle edit mode. But the hair was not added on the assigned surface. It's just a mess and the hair scattered all over the place. I try a combination of modifier arrangement and the "use modifier stack" button. But the result was not satisfactory. Please see the attachment for screen capture and .blend file example. [biru.blend](https://archive.blender.org/developer/F79758/biru.blend) ![hair_error.jpg](https://archive.blender.org/developer/F79756/hair_error.jpg) Thank you

johan tri handoyo commented

2014-03-03 06:14:02 +01:00

Changed status to: 'Open'

johan tri handoyo commented

2014-03-03 06:14:02 +01:00

Added subscriber: @JohanTriHandoyo

Antonis Ryakiotakis commented

2014-03-04 12:50:35 +01:00

Added subscriber: @Psy-Fi

Terry Wallwork commented

2014-03-04 12:54:38 +01:00

Added subscriber: @TerryWallwork-1

Terry Wallwork commented

2014-03-04 12:54:38 +01:00

Confirmed here as well, changing the order of the sub-surf modifer seems to affect it also.

Antonis Ryakiotakis self-assigned this 2014-03-04 19:41:32 +01:00

Antonis Ryakiotakis commented

2014-03-05 18:15:22 +01:00

Some notes here:

Not sure if generative modifiers are currently properly supported for hair (comments in code seem to suggest they are not).

Apart from that there are some things that shout 'wrong' in the code such as line 3400 in particle_edit.c which will return the derived mesh face index in add_pars- [x].num while it's clear that the next function, psys_particle_dm_face_lookup, expects an argument in original mesh index range. I tried changing those but there is still a problem.

What did work was always taking the cached derivedmesh in 3370 but it worked for the wrong reasons and crashed om the particle mirroring functions.

Some notes here: Not sure if generative modifiers are currently properly supported for hair (comments in code seem to suggest they are not). Apart from that there are some things that shout 'wrong' in the code such as line 3400 in particle_edit.c which will return the derived mesh face index in add_pars- [x].num while it's clear that the next function, psys_particle_dm_face_lookup, expects an argument in original mesh index range. I tried changing those but there is still a problem. What did work was always taking the cached derivedmesh in 3370 but it worked for the wrong reasons and crashed om the particle mirroring functions.

Antonis Ryakiotakis commented

2014-03-05 18:52:43 +01:00

OK, looks like indeed the "use modifier stack" option is the reason this breaks. If that is active, the final mesh is used as an emitter while the deformed mesh has been used to plant the hair. This leads to problems naturally. I will check the mirrored code since it misbehaves in the expected correct combination (minor fix + use modifier stack = off).

Antonis Ryakiotakis commented

2014-03-05 19:36:16 +01:00

Mirroring does not work on the same derivedmesh as the add brush does. This likely causes the misalignment between the particles This will be trickier to solve since the mirror code is common to all tools.

Sorry for the spam, just adding information here in case someone wants to take a look too.

Mirroring does not work on the same derivedmesh as the add brush does. This likely causes the misalignment between the particles This will be trickier to solve since the mirror code is common to all tools. Sorry for the spam, just adding information here in case someone wants to take a look too.

blender-admin commented

2014-03-27 10:44:23 +01:00

This issue was referenced by blender/blender-addons-contrib@eca6264ab0

This issue was referenced by blender/blender-addons-contrib@eca6264ab07d63b0875c019d83a2feb48df34fd8

blender-admin commented

2014-03-27 10:44:23 +01:00

This issue was referenced by eca6264ab0

This issue was referenced by eca6264ab07d63b0875c019d83a2feb48df34fd8

Antonis Ryakiotakis commented

2014-03-27 11:17:50 +01:00

Changed status from 'Open' to: 'Resolved'

Antonis Ryakiotakis closed this issue

2014-03-27 11:17:50 +01:00

Antonis Ryakiotakis commented

2014-03-27 11:17:50 +01:00

Closed by commit eca6264ab0.

Closed by commit eca6264ab0.

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Reference: blender/blender#38928

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Adding Blender hair bug #38928