Crash when multiple materials are assigned to a mesh #99371

New Issue

Geoffrey Blackwell · 2022-07-04T04:38:01+02:00

2022-07-04 04:38:01 +02:00

System Information
Operating system: Linux-5.17.15-76051715-generic-x86_64-with-glibc2.35 64 Bits
Graphics card: NVIDIA GeForce RTX 3070 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.103.01

Blender Version
Broken: version: 3.2.1 Release Candidate, branch: master, commit date: 2022-07-01 08:50, hash: 9bb9a54a2a
Worked: unknown (I haven't opened the .blend file in versions older than 3.2. It is broken in 3.2)

Short description of error
When two materials are assigned to the mesh, random faces disappear and reappear when switching between Object and Edit modes. After switching back and forth several times, Blender crashes. In some instances it took significantly more switches from Edit mode to Object mode and back before Blender crashed. In some of these instances, Blender appeared to create new faces with one or more vertices at the object's origin.

When transforming any vertex, edge, or face, Blender quickly generates new faces with at least one vertex at the object origin and crashed shortly thereafter.

I posted a 30-second video of the issue (including two crashes) here: https://www.reddit.com/r/blenderhelp/comments/vqwc1w/strange_face_artifacts_causing_crashes/

Thankfully, I have not reproduced this issue in any other .blend file.

Exact steps for others to reproduce the error

Open the attached file, "Crash - random faces.blend" and you will see the mesh has a number of holes in it.
Press tab and the missing faces will reappear but other faces will disappear. Pressing tab additional times eventually results in Blender crashing.
Select any vertex, edge, or face and transform the selected element using G, S, or R and new faces will appear. Blender will quickly crash.
Reducing the number of material slots to one appears to fix the problem (all faces are visible as normal) but it reappears as soon as a material is assigned to the second slot.

Thank you very much for your time.

Crash - random face orientation.blend

**System Information** Operating system: Linux-5.17.15-76051715-generic-x86_64-with-glibc2.35 64 Bits Graphics card: NVIDIA GeForce RTX 3070 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.103.01 **Blender Version** Broken: version: 3.2.1 Release Candidate, branch: master, commit date: 2022-07-01 08:50, hash: `9bb9a54a2a` Worked: unknown (I haven't opened the .blend file in versions older than 3.2. It is broken in 3.2) **Short description of error** When two materials are assigned to the mesh, random faces disappear and reappear when switching between Object and Edit modes. After switching back and forth several times, Blender crashes. In some instances it took significantly more switches from Edit mode to Object mode and back before Blender crashed. In some of these instances, Blender appeared to create new faces with one or more vertices at the object's origin. When transforming any vertex, edge, or face, Blender quickly generates new faces with at least one vertex at the object origin and crashed shortly thereafter. I posted a 30-second video of the issue (including two crashes) here: https://www.reddit.com/r/blenderhelp/comments/vqwc1w/strange_face_artifacts_causing_crashes/ Thankfully, I have not reproduced this issue in any other .blend file. **Exact steps for others to reproduce the error** 1) Open the attached file, "Crash - random faces.blend" and you will see the mesh has a number of holes in it. 2) Press tab and the missing faces will reappear but other faces will disappear. Pressing tab additional times eventually results in Blender crashing. 3) Select any vertex, edge, or face and transform the selected element using G, S, or R and new faces will appear. Blender will quickly crash. 4) Reducing the number of material slots to one appears to fix the problem (all faces are visible as normal) but it reappears as soon as a material is assigned to the second slot. Thank you very much for your time. [Crash - random face orientation.blend](https://archive.blender.org/developer/F13256461/Crash_-_random_face_orientation.blend)

Geoffrey Blackwell commented

2022-07-04 04:38:01 +02:00

Added subscriber: @Geoffrey-T.Blackwell

Philipp Oeser commented

2022-07-04 12:05:39 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-07-04 12:05:39 +02:00

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

Philipp Oeser commented

2022-07-04 12:05:39 +02:00

Can confirm, will check

Philipp Oeser commented

2022-07-04 12:10:42 +02:00

Added subscriber: @HooglyBoogly

Philipp Oeser commented

2022-07-04 12:10:42 +02:00

This smells like #99191 (Regression: Blender crashes when texture painting (caused by boolean modifers))
We also have a borked mat_nr on an MPoly here (-25964 in this case)

4 _BLI_assert_abort                                                      BLI_assert.c                           46  0x120b68ee 
5 blender::Array<int, 32l, blender::GuardedAllocator>::operator[]        BLI_array.hh                           197 0x4dc3a97  
6 mesh_render_data_polys_sorted_build                                    draw_cache_extract_mesh_render_data.cc 235 0x4dc24db  
7 mesh_render_data_polys_sorted_ensure                                   draw_cache_extract_mesh_render_data.cc 194 0x4dc1893  
8 mesh_render_data_update_polys_sorted                                   draw_cache_extract_mesh_render_data.cc 177 0x4dc17fb  
9 blender::draw::mesh_extract_render_data_node_exec(void * __restrict__) draw_cache_extract_mesh.cc             528 0x4dbb9dc

Other reports that seems to relate to this (invalid material numbers):

#99349 (Crash after apply of boolean modifier and going in sculpt mode)
#99174 (Crash when switching to Sculpt mode)

CC @HooglyBoogly

This smells like #99191 (Regression: Blender crashes when texture painting (caused by boolean modifers)) We also have a borked `mat_nr` on an `MPoly` here (-25964 in this case) ``` 4 _BLI_assert_abort BLI_assert.c 46 0x120b68ee 5 blender::Array<int, 32l, blender::GuardedAllocator>::operator[] BLI_array.hh 197 0x4dc3a97 6 mesh_render_data_polys_sorted_build draw_cache_extract_mesh_render_data.cc 235 0x4dc24db 7 mesh_render_data_polys_sorted_ensure draw_cache_extract_mesh_render_data.cc 194 0x4dc1893 8 mesh_render_data_update_polys_sorted draw_cache_extract_mesh_render_data.cc 177 0x4dc17fb 9 blender::draw::mesh_extract_render_data_node_exec(void * __restrict__) draw_cache_extract_mesh.cc 528 0x4dbb9dc ``` Other reports that seems to relate to this (invalid material numbers): - #99349 (Crash after apply of boolean modifier and going in sculpt mode) - #99174 (Crash when switching to Sculpt mode) CC @HooglyBoogly

Philipp Oeser removed the

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Crash when multiple materials are assigned to a mesh #99371