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Maniphest T60789

Grease Pencil Armature Deform fails with Envelope Deform
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Description

System Information
Operating system: MacOS 10.14
Graphics card: AMD Radeon R9 M395X 4096 MB

Blender Version
Broken: Blender 2.80 beta, jan 23

Short description of error
When using an armature to deform a Grease Pencil object using envelope weights, the GP object fails to deform correctly

Exact steps for others to reproduce the error

Open the following blend file:

GP_bone_envalope_bug.blend752 KBDownload

Here you will find simple GP object and an Armature.

The bone envelopes encompass the entire GP object, so the whole shape should be deformed when moving the bones:

However, what happens is that only a few points actually deform when moving or rotating the bones:

If you compare this to a regular mesh object inside the same file, you can see that with a mesh, all points are being moved correctly:

Related Objects

Event Timeline

William Reynish (billreynish) assigned this task to Antonio Vazquez (antoniov).Jan 23 2019, 11:20 AM
William Reynish (billreynish) created this task.
Jacques Lucke (JacquesLucke) added a subscriber: Jacques Lucke (JacquesLucke).Jan 23 2019, 11:29 AM

Not sure how envelopes are supposed to work but in this example it looks like the issue is that the vertex groups or wrong on the grease pencil object.

Antonio Vazquez (antoniov) lowered the priority of this task from 90 to 30.Jan 23 2019, 11:44 AM
Antonio Vazquez (antoniov) added a subscriber: Joshua Leung (aligorith).

I have looked at the file and yes, the weights are wrong. If you fix the weights, the armature works.

I'm not an expert in armature deformations (I reused deform functions used in meshes), but IIRC, the deformation needs weights. Maybe @Joshua Leung (aligorith) can help us here.

William Reynish (billreynish) added a comment.Jan 23 2019, 11:53 AM

I'm not sure what you mean. When you set the armature to use the envelopes, vertex groups are ignored and not used. This is not related to vertex groups. The envelopes feature is meant to use the envelopes, not the weights.

William Reynish (billreynish) added a comment.Jan 23 2019, 11:54 AM

I'm referring to this feature right here:

William Reynish (billreynish) added a comment.Jan 23 2019, 12:06 PM

Even if a mesh has no weights assigned, you can still deform it if you use Bone Envelopes:

This is the feature which seems to be broken for GP objects

William Reynish (billreynish) added a comment.Jan 23 2019, 12:08 PM

@Antonio Vazquez (antoniov) Is the bug report understood now? As I see it, this is definitely a bug and not an issue with vertex group weights.

Jacques Lucke (JacquesLucke) added a comment.Jan 23 2019, 12:08 PM

Indeed, that seems to be the case. Just the file is a bit misleading because there are vertex groups.

William Reynish (billreynish) added a comment.Jan 23 2019, 12:11 PM

Another bug which is related, is that if you use the envelopes to assign the vertex groups by using Ctrl-P and selecting Bone Envelopes, the weights are not correctly assigned according to the bone envelope sizes.

It could be the same issue? Not sure.

Antonio Vazquez (antoniov) added a comment.Jan 23 2019, 4:09 PM

There is a bug (the envelop does not work witout weights) and a missing feature (the Ctrl+P weights is not supported).

Currently, when you use Ctrl+P with envelopes does the same that vertex group.

I'm going first to look at the bug.

William Reynish (billreynish) raised the priority of this task from 30 to 50.Jan 23 2019, 9:48 PM

Since you can confirm it I'm going to be cheeky and go ahead and set it to confirmed.

Dalai Felinto (dfelinto) removed Antonio Vazquez (antoniov) as the assignee of this task.Dec 23 2019, 4:35 PM
Dalai Felinto (dfelinto) added a project: Tracker Curfew.
Dalai Felinto (dfelinto) added a subscriber: Antonio Vazquez (antoniov).
Philipp Oeser (lichtwerk) added a subscriber: Philipp Oeser (lichtwerk).Feb 7 2020, 4:42 PM
In T60789#605191, @Antonio Vazquez (antoniov) wrote:

There is a bug (the envelop does not work witout weights)

The bug seems to have been fixed

and a missing feature (the Ctrl+P weights is not supported). Currently, when you use Ctrl+P with envelopes does the same that vertex group.

This one is still an issue, not sure if we should call this a missing feature, it is not working as advertised, so either we remove this option for greasepencil, or we call it a bug... going for the latter and have a quick look...
Will also update the report description, since a lot has changed here... maybe even open a separate report for this...

Philipp Oeser (lichtwerk) mentioned this in T73660: Greasepencil parent to armature with envelope weights assigns wrong weights.Feb 7 2020, 4:57 PM
Philipp Oeser (lichtwerk) closed this task as Resolved.Feb 7 2020, 5:00 PM
Philipp Oeser (lichtwerk) claimed this task.

Reported the second issue separately T73660: Greasepencil parent to armature with envelope weights assigns wrong weights.
This way we can close this one.