Empty with Vertex Parent moves to origin when mask modifier hides parent vertex #66440

New Issue

Craig Dolphin · 2019-07-04T18:08:18+02:00

Craig Dolphin commented

2019-07-04 18:08:18 +02:00

System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce MX130/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.25

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-03 22:34, hash: c252fe7a32
Worked: (optional)

Short description of error
If you have an empty parented to a vertex of a mesh, and you apply a mask modifier to the mesh which hides the parent vertex, the empty moves to the mesh object's origin. This behavior is inconsistent with what happens when you hide the parent vertex in edit mode using the h-shortcut. In that case, the empty remains in position relative to the hidden vertex.

I prefer for the empty to retain its position if its parent vertex is hidden by the mask modifier. If this behavior is intentional, or a known limitation of the mask modifier, I haven't been able to find it. Apologies if so.

Hmm. Actually, it seems to move even when I exclude the parent vertex from the mask. ? This is highly confusing. Are mask modifiers incompatible with vertex parenting altogether?

Exact steps for others to reproduce the error
Parent an empty which is not at the world origin to a mesh vertex.
Assign the mesh parent vertex to a vertex group to be used in a mask modifier
Add a mask modifier to the mesh that hides the vertex group
Note that when the modifier is active, the empty has moved to the mesh object's origin
Note that when the modifier is not active, the empty is back in position.

[Based on the default startup or an attached .blend file (as simple as possible)]
mask_vertex_parent_movement.blend
Open file.
Note position of empty sphere.
Turn on mask modifier view port visibility
Note changed position of empty.

***Updated to fix some mistakes in bug report

**System Information** Operating system: Windows-10-10.0.17134 64 Bits Graphics card: GeForce MX130/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 391.25 **Blender Version** Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-03 22:34, hash: `c252fe7a32` Worked: (optional) **Short description of error** If you have an empty parented to a vertex of a mesh, and you apply a mask modifier to the mesh which hides the parent vertex, the empty moves to the mesh object's origin. This behavior is inconsistent with what happens when you hide the parent vertex in edit mode using the h-shortcut. In that case, the empty remains in position relative to the hidden vertex. I prefer for the empty to retain its position if its parent vertex is hidden by the mask modifier. If this behavior is intentional, or a known limitation of the mask modifier, I haven't been able to find it. Apologies if so. Hmm. Actually, it seems to move even when I exclude the parent vertex from the mask. ? This is highly confusing. Are mask modifiers incompatible with vertex parenting altogether? **Exact steps for others to reproduce the error** Parent an empty which is not at the world origin to a mesh vertex. Assign the mesh parent vertex to a vertex group to be used in a mask modifier Add a mask modifier to the mesh that hides the vertex group Note that when the modifier is active, the empty has moved to the mesh object's origin Note that when the modifier is not active, the empty is back in position. [Based on the default startup or an attached .blend file (as simple as possible)] [mask_vertex_parent_movement.blend](https://archive.blender.org/developer/F7566513/mask_vertex_parent_movement.blend) Open file. Note position of empty sphere. Turn on mask modifier view port visibility Note changed position of empty. ***Updated to fix some mistakes in bug report

Craig Dolphin commented

2019-07-04 18:08:18 +02:00

Added subscriber: @CraigD

Craig Dolphin commented

2019-07-04 20:01:21 +02:00

mask_vertex_parent_movement2.blend

So this also seems to apply when the child object is a mesh. I've added to the file to demonstrate this. In this version, the child cube is parented to a vertex in the larger cube. The empty is also parented to a different vertex in the larger cube. The empty's parent vertex is excluded from the mask. The child cube's parent vertex is included in the mask.

In both cases the child objects move to the parent cube's origin when the mask modifier is active.

What's strange is that in my character model blend file, there are some parented empties that do not move when their parent vertex is excluded from the mask, but others that do move once the mask is active regardless of mask vertex group membership.

[mask_vertex_parent_movement2.blend](https://archive.blender.org/developer/F7566668/mask_vertex_parent_movement2.blend) So this also seems to apply when the child object is a mesh. I've added to the file to demonstrate this. In this version, the child cube is parented to a vertex in the larger cube. The empty is also parented to a different vertex in the larger cube. The empty's parent vertex is excluded from the mask. The child cube's parent vertex is included in the mask. In both cases the child objects move to the parent cube's origin when the mask modifier is active. What's strange is that in my character model blend file, there are some parented empties that do not move when their parent vertex is excluded from the mask, but others that do move once the mask is active regardless of mask vertex group membership.

Sebastian Parborg commented

2019-07-05 11:04:20 +02:00

Added subscriber: @ZedDB

Sebastian Parborg commented

2019-07-05 11:04:20 +02:00

Changed status from 'Open' to: 'Archived'

Sebastian Parborg closed this issue

2019-07-05 11:04:20 +02:00

Sebastian Parborg self-assigned this 2019-07-05 11:04:20 +02:00

Sebastian Parborg commented

2019-07-05 11:04:20 +02:00

This is not a bug as this is how the mask modifier works. It removes the masked faces/verts. So the vertex you have parented the object to, no longer exists when the mask is active

Craig Dolphin commented

2019-07-05 18:29:13 +02:00

Alright. I'll leave it alone.

But the point of the second file was that the child object moves even when the parent vertex is not itself masked. So the parent vertex is still present and visible. But maybe the modifier is creating a whole separate mesh to replace the original or something.

Thanks for taking the time to respond.

Alright. I'll leave it alone. But the point of the second file was that the child object moves even **when the parent vertex is not itself masked**. So the parent vertex is still present and visible. But maybe the modifier is creating a whole separate mesh to replace the original or something. Thanks for taking the time to respond.

Philipp Oeser commented

2020-02-26 10:03:55 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2020-02-26 10:03:55 +01:00

Heads up: this should now work, see 5168408ae5

Heads up: this should now work, see 5168408ae5

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Empty with Vertex Parent moves to origin when mask modifier hides parent vertex #66440