Mask Modifier breaks Vertex Parenting #72459

New Issue

Cody Winchester · 2019-12-15T11:56:46+01:00

Cody Winchester commented

2019-12-15 11:56:46 +01:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00

Blender Version
Broken: version: 2.82 (sub 5), branch: master, commit date: 2019-12-14 20:41, hash: dfe965bee2
Worked: (optional)

Short description of error
When using Vertex Parenting to have an object follow a vertices of a mesh that uses a Mask modifier it will sometimes fail to follow when the vertex it is parented to does not get masked. It seems to mostly happen if a lot of the geometry is masked and can be fixed if a modifier like Subsurf is added after the Mask modifier.

Exact steps for others to reproduce the error

Add a subdivided cube 2-3 levels should be fine and apply the modifier.
Add an empty and set its parent to the cube as a Vertex Parent. I do this though python, but it still fails with Ctrl+P vertex parenting.
Add a mask modifier to the cube and create a vertex group and assign it to the modifier.
Set the weights so a portion of the cube is masked, but make sure the vert that the empty is parented to does not get masked.
The empty sometimes will not follow the vertex anymore as if the vertex is masked. In my tests it seems if a lot of the object is masked it will fail and it seems the object is getting reindexed incorrectly. If I add a subsurf modifier after the mask modifier it will work once again.

The uploaded file has an empty parented to a vertex that is not getting masked. If the object's Mask modifier vertex group is set to 'Group' it fails to follow the vertex. If the vertex group is set to 'Group.001' it will follow the vertex despite both vertex group not masking the parent vertex.

Mask Modifier Vertex Parent Bug.blend

This also occurred in 2.79: with-279.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00 **Blender Version** Broken: version: 2.82 (sub 5), branch: master, commit date: 2019-12-14 20:41, hash: `dfe965bee2` Worked: (optional) **Short description of error** When using Vertex Parenting to have an object follow a vertices of a mesh that uses a Mask modifier it will sometimes fail to follow when the vertex it is parented to does not get masked. It seems to mostly happen if a lot of the geometry is masked and can be fixed if a modifier like Subsurf is added after the Mask modifier. **Exact steps for others to reproduce the error** 1. Add a subdivided cube 2-3 levels should be fine and apply the modifier. 2. Add an empty and set its parent to the cube as a Vertex Parent. I do this though python, but it still fails with Ctrl+P vertex parenting. 3. Add a mask modifier to the cube and create a vertex group and assign it to the modifier. 4. Set the weights so a portion of the cube is masked, but make sure the vert that the empty is parented to does not get masked. 5. The empty sometimes will not follow the vertex anymore as if the vertex is masked. In my tests it seems if a lot of the object is masked it will fail and it seems the object is getting reindexed incorrectly. If I add a subsurf modifier after the mask modifier it will work once again. ![image.png](https://archive.blender.org/developer/F8289646/image.png) The uploaded file has an empty parented to a vertex that is not getting masked. If the object's Mask modifier vertex group is set to 'Group' it fails to follow the vertex. If the vertex group is set to 'Group.001' it will follow the vertex despite both vertex group not masking the parent vertex. [Mask Modifier Vertex Parent Bug.blend](https://archive.blender.org/developer/F8222601/Mask_Modifier_Vertex_Parent_Bug.blend) This also occurred in 2.79: [with-279.blend](https://archive.blender.org/developer/F8289662/with-279.blend)

Cody Winchester commented

2019-12-15 11:56:46 +01:00

Added subscriber: @CodyWinchester

Germano Cavalcante commented

2019-12-17 16:07:53 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2019-12-17 16:07:53 +01:00

Apparently, when the number of vertices of the resulting mesh is less than the parent vertex index, parenting is broken.
But the vertex is still there, so it should work.

Apparently, when the number of vertices of the resulting mesh is less than the parent vertex index, parenting is broken. But the vertex is still there, so it should work.

blender-admin commented

2020-01-21 17:52:44 +01:00

This issue was referenced by 5168408ae5

This issue was referenced by 5168408ae50a052d2a9fa795ebdb18820d5b1d67

Sybren A. Stüvel self-assigned this 2020-01-21 17:53:16 +01:00

Sybren A. Stüvel commented

2020-01-21 17:58:19 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Sybren A. Stüvel closed this issue

2020-01-21 17:58:19 +01:00

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Mask Modifier breaks Vertex Parenting #72459