Join 2 GP already rigged (to the same armature) make it lost rigging #103004

New Issue

Samuel Santos · 2022-12-08T03:28:13+01:00

Samuel Santos commented

2022-12-08 03:28:13 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.47

Blender Version
Broken: version: 3.3.1, branch: master, commit date: 2022-10-04 18:35, hash: b292cfe5a9
Worked: Never

Short description of error
When we have two separate Grease Pencil objects rigged to the same armature (with vertex groups) works fine. But when we join the two with "Ctrl+J" the it duplicates the vertex groups (because both have all the same name since it rigged with the same armature) and everything doesn't work properly. With simple rigs only one original GP keeps working, but with more complex rigs everything falls apart.

Exact steps for others to reproduce the error

Create two GP objects with some strokes
Create an armature with one or more bones
Parent both GP objects to the armature using "empty vertex" option
Assign the empty groups to the strokes/points on both GP objects
Move the armature in "pose mode" and both GP objects should move properly
Select both GP objects and "Ctrl+J"
Move the armature in "pose mode" and not all GP strokes moves with the bone

This file has the basics steps until the join: GP Join.blend
From here you can test the bone in pose mode and see both are rigged to the same armature. After selecting both GP objects and doing a join (Ctrl+J) move again the bone.

Maybe the vertex groups should join together since we are using the same armature?

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.47 **Blender Version** Broken: version: 3.3.1, branch: master, commit date: 2022-10-04 18:35, hash: `b292cfe5a9` Worked: Never **Short description of error** When we have two separate Grease Pencil objects rigged to the same armature (with vertex groups) works fine. But when we join the two with "Ctrl+J" the it duplicates the vertex groups (because both have all the same name since it rigged with the same armature) and everything doesn't work properly. With simple rigs only one original GP keeps working, but with more complex rigs everything falls apart. **Exact steps for others to reproduce the error** - Create two GP objects with some strokes - Create an armature with one or more bones - Parent both GP objects to the armature using "empty vertex" option - Assign the empty groups to the strokes/points on both GP objects - Move the armature in "pose mode" and both GP objects should move properly - Select both GP objects and "Ctrl+J" - Move the armature in "pose mode" and not all GP strokes moves with the bone This file has the basics steps until the join: [GP Join.blend](https://archive.blender.org/developer/F14041889/GP_Join.blend) From here you can test the bone in pose mode and see both are rigged to the same armature. After selecting both GP objects and doing a join (Ctrl+J) move again the bone. Maybe the vertex groups should join together since we are using the same armature?

Samuel Santos commented

2022-12-08 03:28:13 +01:00

Added subscriber: @SamuelTelles

Richard Antalik commented

2022-12-08 11:37:16 +01:00

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

Christoph Lendenfeld commented

2022-12-15 11:58:00 +01:00

Added subscriber: @ChrisLend

Christoph Lendenfeld commented

2022-12-15 11:58:00 +01:00

joining geometries merges the vertex groups.
Grease pencil creates a uniquely named group.

Judging by the code this seems to be on purpose calling BKE_object_defgroup_unique_name(vgroup, ob_active); in gpencil_data.c/2873

I'll leave this to the grease pencil team to decide what to do

joining geometries merges the vertex groups. Grease pencil creates a uniquely named group. Judging by the code this seems to be on purpose calling `BKE_object_defgroup_unique_name(vgroup, ob_active);` in gpencil_data.c/2873 I'll leave this to the grease pencil team to decide what to do

Aleš Jelovčan commented

2023-01-09 13:18:33 +01:00

Added subscriber: @frogstomp-4

Aleš Jelovčan self-assigned this 2023-01-09 13:18:33 +01:00

Aleš Jelovčan commented

2023-01-09 13:18:33 +01:00

I'll check.
I see in GP we end up with two bone groups after joining Bone and Bone.001
In mesh join operations we are only left with Bone after joining.

I'll check. I see in GP we end up with two bone groups after joining Bone and Bone.001 In mesh join operations we are only left with Bone after joining.

Antonio Vazquez commented

2023-01-09 13:32:20 +01:00

Added subscriber: @antoniov

Antonio Vazquez commented

2023-01-09 13:33:15 +01:00

@frogstomp-4 yes, the way to go is merge the weights in the vertex group and be sure the index of the vertex group in the point is assigned to the right index of the target object.

Aleš Jelovčan commented

2023-01-09 19:26:51 +01:00

bonefix.diff
@antoniov this fixes the rename issue.
But unrelated, this transform also happens depending on what is selected.
This is true with the fix or not.

2023-01-09 19-24-50.mp4

[bonefix.diff](https://archive.blender.org/developer/F14136228/bonefix.diff) @antoniov this fixes the rename issue. But unrelated, this transform also happens depending on what is selected. This is true with the fix or not. [2023-01-09 19-24-50.mp4](https://archive.blender.org/developer/F14136233/2023-01-09_19-24-50.mp4)

Aleš Jelovčan removed their assignment 2023-02-06 10:23:42 +01:00

Antonio Vazquez was assigned by Aleš Jelovčan

2023-02-06 10:23:42 +01:00

Aleš Jelovčan commented

2023-02-06 10:23:42 +01:00

@antoniov I'm assigning you to the task I could not find a proper solution for.. so it does not get lost.

Antonio Vazquez removed their assignment 2023-02-09 12:18:47 +01:00

Philipp Oeser removed the

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Join 2 GP already rigged (to the same armature) make it lost rigging #103004