particle system volume grid particles out of volume #52732

New Issue

Javier Felip · 2017-09-13T21:19:12+02:00

Javier Felip commented

2017-09-13 21:19:12 +02:00

System Information
OS: Ubuntu 16.04.2 LTS
GPU: TITAN X (Pascal)
CPU: Intel(R) Core(TM) i7-6700K

Blender Version
Broken: 2.78 and 2.79
Worked: unknown

Short description of error
Lines of particles appear from -x to x from the mesh with a high-poly (69451 faces) mesh. After decimating the mesh the problem disappears.

Exact steps for others to reproduce the error
1 - Download a high poly STL (e.g. the stanford bunny (69451 faces) )
http://www-static.cc.gatech.edu/data_files/large_models/bunny.ply.gz

2 - Import mesh
3 - Add a particle system and emit from volume grid.
4 - Set emitter start and end to 0, resolution to 15, physics to NO and size to 0.005
5 - Duplicate
6 - Add a decimation modifier and decimate to 0.01 (693 faces) and apply

Related task: https://developer.blender.org/T46481

particleVolumeGridProblem.blend

**System Information** OS: Ubuntu 16.04.2 LTS GPU: TITAN X (Pascal) CPU: Intel(R) Core(TM) i7-6700K **Blender Version** Broken: 2.78 and 2.79 Worked: unknown **Short description of error** Lines of particles appear from -x to x from the mesh with a high-poly (69451 faces) mesh. After decimating the mesh the problem disappears. **Exact steps for others to reproduce the error** 1 - Download a high poly STL (e.g. the stanford bunny (69451 faces) ) http://www-static.cc.gatech.edu/data_files/large_models/bunny.ply.gz 2 - Import mesh 3 - Add a particle system and emit from volume grid. 4 - Set emitter start and end to 0, resolution to 15, physics to NO and size to 0.005 5 - Duplicate 6 - Add a decimation modifier and decimate to 0.01 (693 faces) and apply Related task: https://developer.blender.org/T46481 [particleVolumeGridProblem.blend](https://archive.blender.org/developer/F795577/particleVolumeGridProblem.blend)

Javier Felip commented

2017-09-13 21:19:12 +02:00

Changed status to: 'Open'

Javier Felip commented

2017-09-13 21:19:12 +02:00

Added subscriber: @xavisomah

Javier Felip changed title from ~~particle system volume grid~~ to particle system volume grid particles out of volume

2017-09-13 21:19:34 +02:00

Sergey Sharybin commented

2017-09-14 11:28:21 +02:00

Added subscribers: @mont29, @Sergey

Bastien Montagne was assigned by Sergey Sharybin

2017-09-14 11:28:21 +02:00

Sergey Sharybin commented

2017-09-14 11:28:21 +02:00

The issue here is caused by failed isect_axial_line_segment_tri_v3. This patch will allow to catch that case: P529. What i'm not sure about, is why to use axial here? At least, for volume distribution. Would think something like this will make it: P530. This patch solves this issue.

@mont29, mind having a second pair of eyes here? :)

There are still issues on other grid resolutions, but those are caused by non-manifold nature of the model.

The issue here is caused by failed `isect_axial_line_segment_tri_v3`. This patch will allow to catch that case: [P529](https://archive.blender.org/developer/P529.txt). What i'm not sure about, is why to use axial here? At least, for volume distribution. Would think something like this will make it: [P530](https://archive.blender.org/developer/P530.txt). This patch solves this issue. @mont29, mind having a second pair of eyes here? :) There are still issues on other grid resolutions, but those are caused by non-manifold nature of the model.

Bastien Montagne commented

2017-09-14 13:10:54 +02:00

@Sergey no idea really why that intersection algo was chosen, would bet it was best available in our code at the time. ;)

So if watertight works better, P530 looks totally fine to me.

@Sergey no idea really why that intersection algo was chosen, would bet it was best available in our code at the time. ;) So if watertight works better, [P530](https://archive.blender.org/developer/P530.txt) looks totally fine to me.

Bastien Montagne was unassigned by Sergey Sharybin

2017-09-14 14:11:00 +02:00

Sergey Sharybin self-assigned this 2017-09-14 14:11:00 +02:00

Sergey Sharybin commented

2017-09-14 14:11:00 +02:00

@mont29, ok, will steal the report back to self, run additional tests and commit fix.

blender-admin commented

2017-09-14 16:43:00 +02:00

This issue was referenced by c75bd25cd8

This issue was referenced by c75bd25cd87e8648749f4b19bc90c269b2431251

Sergey Sharybin commented

2017-09-14 16:56:48 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2017-09-14 16:56:48 +02:00

gimble commented

2017-09-15 04:43:49 +02:00

Added subscriber: @gimble

gimble commented

2017-09-15 04:43:49 +02:00

OS: Ubuntu 16.04

Is this truly fixed, or am I overlooking something obvious?
It seems that now no particles appear, unless you press 'invert grid'

I double checked to be sure. The following blend file works "sort of" in 2.79 official - particles appear, but some are outside the "watermelon" shape object.
volume_grid_test.blend

OS: Ubuntu 16.04 Is this truly fixed, or am I overlooking something obvious? It seems that now no particles appear, unless you press 'invert grid' I double checked to be sure. The following blend file works "sort of" in 2.79 official - particles appear, but some are outside the "watermelon" shape object. [volume_grid_test.blend](https://archive.blender.org/developer/F801593/volume_grid_test.blend)

Sergey Sharybin commented

2017-09-15 08:36:22 +02:00

Made a mistake in original patch which broke quad faces. Fixed in 95a8e73d40.

Made a mistake in original patch which broke quad faces. Fixed in 95a8e73d40.

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particle system volume grid particles out of volume #52732