Alembic import crashes Blender #74200

New Issue

Helmut Schulz · 2020-02-25T16:36:01+01:00

Helmut Schulz commented

2020-02-25 16:36:01 +01:00

System Information
Operating system: Linux Ubuntu 16.04
Graphics card: Geforce 1050ti

Blender Version
Broken: 2.79, 2.80, 2.82
Worked: never

Short description of error
Alembic import of attached file crashes Blender immediately, message printed on console:
"Malloc returns null: len=18446744073709154320 in mesh_render_data_create_ex, total 24824732"

File contains mesh data with changing topology (some cloth simulated flying "paper" letters hitting a collider).
Tested on two similar machines, both running Ubuntu. Same symptom.

Exact steps for others to reproduce the error
Import file attached (exported from Houdini 18, loads back into Houdini 18 without complaints)
Based on the default startup or an attached .blend file (as simple as possible).s10-letters-rewrite.abc

**System Information** Operating system: Linux Ubuntu 16.04 Graphics card: Geforce 1050ti **Blender Version** Broken: 2.79, 2.80, 2.82 Worked: never **Short description of error** Alembic import of attached file crashes Blender immediately, message printed on console: "Malloc returns null: len=18446744073709154320 in mesh_render_data_create_ex, total 24824732" File contains mesh data with changing topology (some cloth simulated flying "paper" letters hitting a collider). Tested on two similar machines, both running Ubuntu. Same symptom. **Exact steps for others to reproduce the error** Import file attached (exported from Houdini 18, loads back into Houdini 18 without complaints) Based on the default startup or an attached .blend file (as simple as possible).[s10-letters-rewrite.abc](https://archive.blender.org/developer/F8369464/s10-letters-rewrite.abc)

Helmut Schulz commented

2020-02-25 16:36:02 +01:00

Added subscriber: @thorbad

Ankit Meel commented

2020-02-25 17:12:37 +01:00

Added subscriber: @ankitm

Ankit Meel commented

2020-02-25 17:12:37 +01:00

  BLI_assert failed: source/blender/blenlib/intern/math_geom_inline.c:254, poly_to_tri_count(), at '!poly_count || corner_count > poly_count * 2'
  poly_count	const int	8596
  corner_count	const int	16

``` BLI_assert failed: source/blender/blenlib/intern/math_geom_inline.c:254, poly_to_tri_count(), at '!poly_count || corner_count > poly_count * 2' poly_count const int 8596 corner_count const int 16

Philipp Oeser commented

2020-02-26 09:56:55 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Pawel Franitza commented

2020-02-29 13:29:16 +01:00

Added subscriber: @Rongix

Pawel Franitza commented

2020-02-29 13:29:16 +01:00

File is broken. You should export alembic as quads/triangles, not 'n-gons/point' cloud. Please remesh and adjust scale of your scene before importing to Blender.

Desktop 2020.02.29 - 12.40.09.01.mp4

File is broken. You should export alembic as quads/triangles, not 'n-gons/point' cloud. Please remesh and adjust scale of your scene before importing to Blender. [Desktop 2020.02.29 - 12.40.09.01.mp4](https://archive.blender.org/developer/F8379939/Desktop_2020.02.29_-_12.40.09.01.mp4)

Helmut Schulz commented

2020-02-29 13:48:53 +01:00

As said, could import back into Houdini, and Guerilla Render/Station could deal with it too, so it can't be utterly broken. Had no chance to find out what was wrong with it in regard to Blender though due to Blender's quick and ungraceful exit - even if some stuff is out of spec, bailing out with a core dump isn't what it should do, straight and square.

Meanwhile I found a workaround btw, adding subdivision in Houdini before exporting it helps (had already tried a remesh before I wrote the report here, without success though).

In #74200#882598, @Rongix wrote:
File is broken. You should export alembic as quads/triangles, not 'n-gons/point' cloud. Please remesh and adjust scale of your scene before importing to Blender.

As said, could import back into Houdini, and Guerilla Render/Station could deal with it too, so it can't be utterly broken. Had no chance to find out what was wrong with it in regard to Blender though due to Blender's quick and ungraceful exit - even if some stuff is out of spec, bailing out with a core dump isn't what it should do, straight and square. Meanwhile I found a workaround btw, adding subdivision in Houdini before exporting it helps (had already tried a remesh before I wrote the report here, without success though). > In #74200#882598, @Rongix wrote: > File is broken. You should export alembic as quads/triangles, not 'n-gons/point' cloud. Please remesh and adjust scale of your scene before importing to Blender. >

Sybren A. Stüvel self-assigned this 2020-03-10 14:36:44 +01:00

Pawel Franitza commented

2020-03-10 14:43:22 +01:00

Removed subscriber: @Rongix

blender-admin commented

2020-03-10 17:15:29 +01:00

This issue was referenced by a6d7280b8e

This issue was referenced by a6d7280b8e1c8ac7c0d6ebcf134290836413168c

Sybren A. Stüvel commented

2020-03-10 17:16:34 +01:00

The file is certainly broken, as it's not accepted by Gaffer or the USD Alembic plugin either (both complain about invalid mesh data).

Sybren A. Stüvel commented

2020-03-10 17:23:34 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Sybren A. Stüvel closed this issue

2020-03-10 17:23:34 +01:00

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Reference: blender/blender#74200

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Alembic import crashes Blender #74200