ShapeKey does not "see" modified Vertex Group (e.g. proximity modifier, dynamic paint) #90276

New Issue

Everton Schneider · 2021-07-28T20:31:41+02:00

Everton Schneider commented

2021-07-28 20:31:41 +02:00

System Information
Operating system: Linux-5.11.0-25-generic-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.57.02

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-07-28 16:16, hash: 3bf9675849
Worked: I don't know...

Short description of error
I'm not sure if it's a bug...
The "vertex group" option inside shape keys is not using the "modified" result of the vertex group modifier for example proximity. Not even using the result of geometry nodes modified vertex group.

Exact steps for others to reproduce the error
Just open the prepared blend file and you will see methods:

Painted = Just randomly painted the vertex group and use it to "limit" the "cast"(cast modifier applied as shape) shape key.
Proximity modifier = A modified vertex group (all weights set to 1.0) via proximity modifier and I'm trying to feed the "vertex group" shape key dropdown menu but it seems to use the original vertex group and not the modified one (I'm not sure if it's a bug or if it misses the option to choose between original or modified vertex group).
Geometry Nodes = A proximity attribute mixed with the vertex group to get the same effect as proximity modifier and overwriting the vertex group and I'm trying to feed the "vertex group" shape key dropdown menu but it seems to use the original vertex group and not the modified one.

ShapeKey_VertexGroup.blend

**System Information** Operating system: Linux-5.11.0-25-generic-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce RTX 2080 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.57.02 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-07-28 16:16, hash: `3bf9675849` Worked: I don't know... **Short description of error** I'm not sure if it's a bug... The "vertex group" option inside shape keys is not using the "modified" result of the vertex group modifier for example proximity. Not even using the result of geometry nodes modified vertex group. **Exact steps for others to reproduce the error** Just open the prepared blend file and you will see methods: - Painted = Just randomly painted the vertex group and use it to "limit" the "cast"(cast modifier applied as shape) shape key. - Proximity modifier = A modified vertex group (all weights set to 1.0) via proximity modifier and I'm trying to feed the "vertex group" shape key dropdown menu but it seems to use the original vertex group and not the modified one (I'm not sure if it's a bug or if it misses the option to choose between original or modified vertex group). - Geometry Nodes = A proximity attribute mixed with the vertex group to get the same effect as proximity modifier and overwriting the vertex group and I'm trying to feed the "vertex group" shape key dropdown menu but it seems to use the original vertex group and not the modified one. [ShapeKey_VertexGroup.blend](https://archive.blender.org/developer/F10243461/ShapeKey_VertexGroup.blend)

Everton Schneider commented

2021-07-28 20:31:41 +02:00

Added subscriber: @EvertonSchneider

blender-admin commented

2021-07-28 20:31:41 +02:00

#97995 was marked as duplicate of this issue

blender-admin commented

2021-07-28 20:31:41 +02:00

#97845 was marked as duplicate of this issue

blender-admin commented

2021-07-28 20:31:41 +02:00

#97767 was marked as duplicate of this issue

Philipp Oeser commented

2021-07-29 10:36:49 +02:00

Added subscribers: @JacquesLucke, @mont29, @lichtwerk

Philipp Oeser commented

2021-07-29 10:36:49 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2021-07-29 10:36:49 +02:00

I can confirm the behavior, but don t think this is a bug, more of a design question.

Even though shapekeys are internally a modifier as well (a "VirtualModifier"), they are always evaluated before other/real modifiers.
To be able to "see" the modifications of other modifiers, shapekeys would need to be evaluated later in the stack (and I am not sure if this would run into dependency cycles along the way).

It might be possible to introduce a shapekey Geometry Nodes node (or you could build the shapekey yourself in Geometry nodes - interpolating existing meshes based on the vertexgroups) and inside the "real" modifer satck this would all work nicely. For the shapekeys as they are right now (sitting in the front of modifiers evaluation), I dont think it is possible for them to "see" vertexgroup manipulations of later modifiers.

Maybe core developers can confirm?
@mont29
@JacquesLucke

I can confirm the behavior, but don t think this is a bug, more of a design question. Even though shapekeys are internally a modifier as well (a "VirtualModifier"), they are always evaluated before other/real modifiers. To be able to "see" the modifications of other modifiers, shapekeys would need to be evaluated later in the stack (and I am not sure if this would run into dependency cycles along the way). It might be possible to introduce a shapekey `Geometry Nodes` node (or you could build the shapekey yourself in Geometry nodes - interpolating existing meshes based on the vertexgroups) and inside the "real" modifer satck this would all work nicely. For the shapekeys as they are right now (sitting in the front of modifiers evaluation), I dont think it is possible for them to "see" vertexgroup manipulations of later modifiers. Maybe core developers can confirm? @mont29 @JacquesLucke

Everton Schneider commented

2021-07-30 20:03:17 +02:00

(or you could build the shapekey yourself in Geometry nodes - interpolating existing meshes based on the vertexgroups)

This is an interesting way. I will try to do this. If you have some clue on how to build this please let me know...

It might be possible to introduce a shapekey Geometry Nodes node

For now, the way that it's implemented, without the need to rewrite the entire Shape Key code, is it possible to "expose" the shape key in the modifier stack and let the user decide the evaluation order? Just like "Collision" for example... it's there just to change the order but it's in the Physics Properties... (please... forgive me... I don't know how it works... just thinking here...)

> (or you could build the shapekey yourself in Geometry nodes - interpolating existing meshes based on the vertexgroups) This is an interesting way. I will try to do this. If you have some clue on how to build this please let me know... > It might be possible to introduce a shapekey Geometry Nodes node For now, the way that it's implemented, without the need to rewrite the entire Shape Key code, is it possible to "expose" the shape key in the modifier stack and let the user decide the evaluation order? Just like "Collision" for example... it's there just to change the order but it's in the Physics Properties... (please... forgive me... I don't know how it works... just thinking here...)

Bastien Montagne commented

2021-09-29 17:44:54 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Archived'

Bastien Montagne closed this issue

2021-09-29 17:44:54 +02:00

Bastien Montagne commented

2021-09-29 17:44:54 +02:00

This is indeed not a bug, but as pointed above, a result of current internal handling of shape keys. Thanks for the report anyway.

Philipp Oeser changed title from ~~ShapeKey Vertex Group~~ to ShapeKey does not "see" modified Vertex Group (e.g. proximity modifier, dynamic paint)

2022-05-02 10:02:51 +02:00

Philipp Oeser commented

2022-05-02 10:03:16 +02:00

Added subscriber: @exverxes

Aleksander Wisniewski commented

2022-05-02 18:08:07 +02:00

As my task was merged to this already closed ticket, I would like to add a note:

This might not be a bug as in error in the code, but from the UX perspective it is something that does not work as one would expect. Current behaviour is not consistent with the rest of the application where you are able to use weights that were generated by either dynamic paint or by weight paint proximity modifier. It's good that there is a possible work around using nodes and I will definitely try that, but to be honest this is just a work around of functionality that from the user point of view is not working as one would expect. I understand that fixing this might be problematic, but honestly it would be good to do this so that whole blender package is consistent in its behaviour.

As my task was merged to this already closed ticket, I would like to add a note: This might not be a bug as in error in the code, but from the UX perspective it is something that does not work as one would expect. Current behaviour is not consistent with the rest of the application where you are able to use weights that were generated by either dynamic paint or by weight paint proximity modifier. It's good that there is a possible work around using nodes and I will definitely try that, but to be honest this is just a work around of functionality that from the user point of view is not working as one would expect. I understand that fixing this might be problematic, but honestly it would be good to do this so that whole blender package is consistent in its behaviour.

Philipp Oeser commented

2022-05-04 13:32:36 +02:00

Added subscriber: @kcanon

Philipp Oeser commented

2022-05-10 08:58:59 +02:00

Added subscriber: @unknowndinodev

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ShapeKey does not "see" modified Vertex Group (e.g. proximity modifier, dynamic paint) #90276