Regression: Skin and Miffor modifiers cause mesh collapse #108880

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opened 2023-06-12 11:31:20 +02:00 by Andrew Ryan · 3 comments

Andrew Ryan commented

2023-06-12 11:31:20 +02:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 531.61

Blender Version
Broken: version: 3.6.0 Beta, branch: blender-v3.6-release, commit date: 2023-06-10 13:37, hash: d79524e3098e
Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-06-12 00:30, hash: f4d6edd4764a
Worked: (version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: e1ccd9d4a1d3)

Caused by 4369627e71

Short description of error
Combination of Skin and Mirror modifiers leads to collapse of the generated mesh
and 'No valid root vertex found' error ,
if the Skin modifier root vertex lies on the mirror axis.

Exact steps for others to reproduce the error

Create a vertex and extrude it a few times.
Add Mirror modifier (move mirror modifier to the top of the stack).
Add Skin modifier and mark a vertex as root.

If the root vertex lies on the mirror axis the mesh collapses
and You get an 'No valid root vertex found' error.

If you mark as root some other vertex not on mirror axis the modifier works correctly.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 531.61 **Blender Version** Broken: version: 3.6.0 Beta, branch: blender-v3.6-release, commit date: 2023-06-10 13:37, hash: `d79524e3098e` Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-06-12 00:30, hash: `f4d6edd4764a` Worked: (version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: `e1ccd9d4a1d3`) Caused by 4369627e7143e7c9c7df75e42ec8eb2e8370fd34 **Short description of error** Combination of Skin and Mirror modifiers leads to collapse of the generated mesh and 'No valid root vertex found' error , if the Skin modifier root vertex lies on the mirror axis. **Exact steps for others to reproduce the error** 1. Create a vertex and extrude it a few times. 2. Add Mirror modifier (move mirror modifier to the top of the stack). 3. Add Skin modifier and mark a vertex as root. If the root vertex lies on the mirror axis the mesh collapses and You get an 'No valid root vertex found' error. If you mark as root some other vertex not on mirror axis the modifier works correctly.

skin_bug.blend

804 KiB

Andrew Ryan added the

labels 2023-06-12 11:31:20 +02:00

Iliya Katushenock added the

labels 2023-06-12 11:41:30 +02:00

Iliya Katushenock changed title from ~~Skin modifier mesh collapse~~ to Regression: Skin and Miffor modifiers cause mesh collapse

2023-06-12 11:42:06 +02:00

Philipp Oeser commented

2023-06-12 11:44:53 +02:00

Member

Can confirm, will check.

Can confirm, will check.

Philipp Oeser added

and removed

labels 2023-06-12 11:45:00 +02:00

Iliya Katushenock added

and removed

labels 2023-06-12 12:42:44 +02:00

Philipp Oeser commented

2023-06-12 12:57:11 +02:00

Member

Caused by 4369627e71

Caused by 4369627e7143e7c9c7df75e42ec8eb2e8370fd34 CC @mano-wii

Philipp Oeser added

and removed

labels 2023-06-12 12:57:39 +02:00

Germano Cavalcante commented

2023-06-12 16:19:57 +02:00

Member

This is a tricky one to fix.
Before, although it worked well for mirror, for other forms of weld it could cause problems.
For example, each geometry island should only have 1 root, but weld can merge islands. In these cases which root should remain?
Also, apparently there isn't an API for Mesh that detects islands (that's just for BMesh).

(Perhaps, the solution is to resolve only for Mirror).

This is a tricky one to fix. Before, although it worked well for mirror, for other forms of weld it could cause problems. For example, each geometry island should only have 1 root, but weld can merge islands. In these cases which root should remain? Also, apparently there isn't an API for Mesh that detects islands (that's just for BMesh). (Perhaps, the solution is to resolve only for Mirror).

Germano Cavalcante referenced a pull request that will close this issue

2023-06-12 23:37:11 +02:00

WIP: Fix #108880: Skin and Miffor modifiers cause mesh collapse #108915

Germano Cavalcante referenced this issue from a commit

2023-06-13 00:06:42 +02:00

Fix #108880: Skin and Miffor modifiers cause mesh collapse

Germano Cavalcante closed this issue

2023-06-13 00:07:17 +02:00

Blender Bot added

and removed

labels 2023-06-13 00:07:19 +02:00

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