Rebuilding multires subdivisions sometimes puts some vertices at the origin #81645

New Issue

Thomas Larsson · 2020-10-12T09:42:15+02:00

Thomas Larsson commented

2020-10-12 09:42:15 +02:00

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: Quadro K2200/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 385.54

Blender Version
Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: 0330d1af29
Worked: (newest version of Blender that worked as expected)

Short description of error

Add multires modifier
Rebuild subdivisions.
Some vertices end up at the origin.

If you apply the multires modifier, the problem vertices are [60074, 60075, 60076, 60081, 60082, 60083, 60088, 60089, 60090]. Applying the modifier apparently changes vertex numbers, since those vertices were located in the shaft area in the original HD mesh.

multires-problem.blend

**System Information** Operating system: Windows-7-6.1.7601-SP1 64 Bits Graphics card: Quadro K2200/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 385.54 **Blender Version** Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: `0330d1af29` Worked: (newest version of Blender that worked as expected) **Short description of error** 1. Add multires modifier 2. Rebuild subdivisions. 3. Some vertices end up at the origin. If you apply the multires modifier, the problem vertices are [60074, 60075, 60076, 60081, 60082, 60083, 60088, 60089, 60090]. Applying the modifier apparently changes vertex numbers, since those vertices were located in the shaft area in the original HD mesh. ![multires-problem.png](https://archive.blender.org/developer/F8981678/multires-problem.png) [multires-problem.blend](https://archive.blender.org/developer/F8981671/multires-problem.blend)

Thomas Larsson commented

2020-10-12 09:42:15 +02:00

Added subscriber: @thomasl-3

Germano Cavalcante commented

2020-10-13 15:48:51 +02:00

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

Germano Cavalcante commented

2020-10-13 15:48:51 +02:00

Added subscriber: @mano-wii

Matt commented

2020-10-13 17:42:41 +02:00

Added subscriber: @mattli911

Matt commented

2020-10-13 17:42:41 +02:00

I've seen something similar, where verts randomly explode/fly off. It might be related to having N-Gons but I'm still not sure either... Although I think in my case, it wasn't going to 0,0,0, but some other random spot.

Thomas Larsson commented

2021-02-17 06:07:12 +01:00

I think I have another instance of the same bug. Look at the vertex behind the last tooth at resolution 0, 1, and 2. Unfortunately the mesh is as heavy as before.

multires-tooth.blend

I think I have another instance of the same bug. Look at the vertex behind the last tooth at resolution 0, 1, and 2. Unfortunately the mesh is as heavy as before. ![last-tooth.png](https://archive.blender.org/developer/F9811225/last-tooth.png) [multires-tooth.blend](https://archive.blender.org/developer/F9811227/multires-tooth.blend)

Thomas Larsson commented

2021-02-17 07:37:27 +01:00

The stray vertices snap back into position once the multires modifier is applied.

The stray vertices snap back into position once the multires modifier is applied. ![apply-multires.png](https://archive.blender.org/developer/F9811369/apply-multires.png)

Thomas Larsson commented

2021-02-17 12:58:26 +01:00

Somebody pointed out that applying the multires modifier implicitly moves it to the top of the stack. If you apply the armature modifier first and then the multires, the problem persists. In the dense mesh, the offending vertices are 204528 and 208935. The location of the first vertex and its nearest neighbors (those selected in picture below) are

41418  (0.02633 -0.02200 1.61317)
204527  (0.02452 -0.02216 1.61140)
204528  (0.01776 -0.02561 1.62735) ***
204529  (0.02578 -0.02123 1.61255)
204531  (0.02334 -0.02185 1.61031)

Since the base mesh has 16556 vertices, the problem is a level 2 vertex, which has one level 1 and three level 2 neighbors, and no level 0 neighbor.

Somebody pointed out that applying the multires modifier implicitly moves it to the top of the stack. If you apply the armature modifier first and then the multires, the problem persists. In the dense mesh, the offending vertices are 204528 and 208935. The location of the first vertex and its nearest neighbors (those selected in picture below) are ``` ``` 41418 (0.02633 -0.02200 1.61317) 204527 (0.02452 -0.02216 1.61140) 204528 (0.01776 -0.02561 1.62735) *** 204529 (0.02578 -0.02123 1.61255) 204531 (0.02334 -0.02185 1.61031) ``` ``` Since the base mesh has 16556 vertices, the problem is a level 2 vertex, which has one level 1 and three level 2 neighbors, and no level 0 neighbor. ![selected.png](https://archive.blender.org/developer/F9811969/selected.png)

Philipp Oeser removed the

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Rebuilding multires subdivisions sometimes puts some vertices at the origin #81645