Update bug when using Vertex Parents, and armatures #38395

New Issue

Keen Foong · 2014-01-29T14:11:21+01:00

Keen Foong commented

2014-01-29 14:11:21 +01:00

System Information
Windows 7 x64 Professional
nVidia GeForce GTX 580
Intel Core i7 CPU x980

Blender Version
Broken: 2.69.10 1c29fd7
It also happens for blender official 2.69

Constrained bones don't update when using vertex parents. Bones constrained to an empty, which is vertex parented to a mesh, wont update properly if the mesh is deformed by anything.

Some Notes

The constrained bones wont go back to the right places if you cancel the deformation by using move,rotate or scale then right click.
The constrained bones wont go back to the original places if you reset the transformations (alt-g, alt-r, alt-s)
Also the updates for the constrained objects lag behind when you move the bones around.

The reason why I'm doing it this way is to keep controls on a specific part of a mesh even if the mesh deforms such as the mouth control.

Attached blend file
vertexparentbonesupdates.blend

Try moving the main bone (UpdateBugBone01, or UpdateBugBone02) in pose mode then right clicking
Move or rotate the main bones then press alt-g or alt-r to reset them.

Steps to reproduce error

Create Cube and Empty
Select Empty first then the Cube
Go into edit mode and select any vertex
Press Ctrl-P to set the Vertex Parent to the empty.
Create a Bone (X)
Add Bone Constraint -> "Copy Location"
Set Target to the Empty
Create a new Bone (Y)

Add weight to Bone (Y) so the bone can deform the Cube

vertexparentbonesupdates_simple.blend (Created from the above steps)

Once that is done you can try the following to get the update bug

Move Bone (Y) in Pose mode, then right click to cancel the move
Move Bone (Y) in Pose mode, then place it. Use Alt-G to reset the position.

Let me know if anything is unclear.

**System Information** Windows 7 x64 Professional nVidia GeForce GTX 580 Intel Core i7 CPU x980 **Blender Version** Broken: 2.69.10 1c29fd7 It also happens for blender official 2.69 Constrained bones don't update when using vertex parents. Bones constrained to an empty, which is vertex parented to a mesh, wont update properly if the mesh is deformed by anything. **Some Notes** - The constrained bones wont go back to the right places if you cancel the deformation by using move,rotate or scale then right click. - The constrained bones wont go back to the original places if you reset the transformations (alt-g, alt-r, alt-s) - Also the updates for the constrained objects lag behind when you move the bones around. The reason why I'm doing it this way is to keep controls on a specific part of a mesh even if the mesh deforms such as the mouth control. **Attached blend file** [vertexparentbonesupdates.blend](https://archive.blender.org/developer/F75571/vertexparentbonesupdates.blend) - Try moving the main bone (UpdateBugBone01, or UpdateBugBone02) in pose mode then right clicking - Move or rotate the main bones then press alt-g or alt-r to reset them. **Steps to reproduce error** - Create Cube and Empty - Select Empty first then the Cube - Go into edit mode and select any vertex - Press Ctrl-P to set the Vertex Parent to the empty. - Create a Bone (X) - Add Bone Constraint -> "Copy Location" - Set Target to the Empty - Create a new Bone (Y) # Add weight to Bone (Y) so the bone can deform the Cube [vertexparentbonesupdates_simple.blend](https://archive.blender.org/developer/F75572/vertexparentbonesupdates_simple.blend) (Created from the above steps) Once that is done you can try the following to get the update bug - Move Bone (Y) in Pose mode, then right click to cancel the move - Move Bone (Y) in Pose mode, then place it. Use Alt-G to reset the position. Let me know if anything is unclear.

Keen Foong commented

2014-01-29 14:11:21 +01:00

Changed status to: 'Open'

Keen Foong commented

2014-01-29 14:11:21 +01:00

Added subscriber: @kfoong

Brecht Van Lommel commented

2014-01-29 15:23:33 +01:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2014-01-29 15:23:33 +01:00

Brecht Van Lommel self-assigned this 2014-01-29 15:23:33 +01:00

Brecht Van Lommel commented

2014-01-29 15:23:33 +01:00

This is currently the intended behavior if there is a dependency cycle. This is printed in the console:

Dependency cycle detected:
  Cube depends on Armature through Armature Modifier.
  Empty.002 depends on Cube through Vertex Parent.
  Armature depends on Empty.002 through Copy Location.

http://wiki.blender.org/index.php/Dev:Source/Data_System/Dependency_Graph/Overview

Basically if there is a cycle updates will lag. Work on the dependency graph is ongoing and this may be changed at some point or communicated better, or the cycle may be possible to avoid in a more advanced system, but at the moment this is not a bug.

This is currently the intended behavior if there is a dependency cycle. This is printed in the console: ``` Dependency cycle detected: Cube depends on Armature through Armature Modifier. Empty.002 depends on Cube through Vertex Parent. Armature depends on Empty.002 through Copy Location. ``` http://wiki.blender.org/index.php/Dev:Source/Data_System/Dependency_Graph/Overview Basically if there is a cycle updates will lag. Work on the dependency graph is ongoing and this may be changed at some point or communicated better, or the cycle may be possible to avoid in a more advanced system, but at the moment this is not a bug.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Update bug when using Vertex Parents, and armatures #38395

Add weight to Bone (Y) so the bone can deform the Cube