Bone Action Constraints with shared Action leads to glitches #48234

New Issue

Paul R · 2016-04-22T04:49:06+02:00

Paul R commented

2016-04-22 04:49:06 +02:00

System Information
Suse Leap 42.1
NVidia GTX 560ti (official drivers)

Blender Version
Broken: 2.77a
Worked: -

Short description of error
If Bone Action Constraints are assigned to bones in different armatures and all share the same Action, the animation will usually glitch if two or more targets are moved at the same time. Affects view-port and final renders.

Example video:
https://www.youtube.com/watch?v=uYD3E5xaJag&t=41

Exact steps for others to reproduce the error

open .blend blender_bone_action_constraints_bug.blend
select all Empties
move slowly along Z axis
bone animations will glitch

Workaround

create copies of the original Action - one for each bone/constraint
(looks like Blender might be caching the Action positions?)

**System Information** Suse Leap 42.1 NVidia GTX 560ti (official drivers) **Blender Version** Broken: 2.77a Worked: - **Short description of error** If Bone Action Constraints are assigned to bones in different armatures and all share the same Action, the animation will usually glitch if two or more targets are moved at the same time. Affects view-port and final renders. Example video: https://www.youtube.com/watch?v=uYD3E5xaJag&t=41 **Exact steps for others to reproduce the error** - open .blend [blender_bone_action_constraints_bug.blend](https://archive.blender.org/developer/F304790/blender_bone_action_constraints_bug.blend) - select all Empties - move slowly along Z axis - bone animations will glitch **Workaround** - create copies of the original Action - one for each bone/constraint (looks like Blender might be caching the Action positions?)

Paul R commented

2016-04-22 04:49:06 +02:00

Changed status to: 'Open'

Paul R commented

2016-04-22 04:49:06 +02:00

Added subscriber: @intracube

Bastien Montagne commented

2016-04-22 13:06:01 +02:00

Added subscribers: @Sergey, @mont29

Bastien Montagne commented

2016-04-22 13:06:01 +02:00

This is a threading issue (running Blender mono-threaded, with -t 1 command line option, shows no problem). We are evaluating the same action in parallel for different frames, fiddling with its update flags, etc. No good.

@Sergey from quick look, think we can either:

Lock around action evaluation itself (last part of what_does_obaction(), or maybe even in constraint exec itself).
Make temp copy of action for its evaluation (but would expect this to be overkilling?).
Change depsgraph to check this situation??? Doubt this is really doable or desired though.

First solution sounds simpler one to me, but likely not the optimal one…

This is a threading issue (running Blender mono-threaded, with `-t 1` command line option, shows no problem). We are evaluating the same action in parallel for different frames, fiddling with its update flags, etc. No good. @Sergey from quick look, think we can either: * Lock around action evaluation itself (last part of `what_does_obaction()`, or maybe even in constraint exec itself). * Make temp copy of action for its evaluation (but would expect this to be overkilling?). * Change depsgraph to check this situation??? Doubt this is really doable or desired though. First solution sounds simpler one to me, but likely not the optimal one…

Paul R commented

2016-05-07 12:40:05 +02:00

In #48234#371151, @mont29 wrote:
This is a threading issue (running Blender mono-threaded, with -t 1 command line option, shows no problem).

Ah, thanks.

Can confirm that -t 1 fixes the issue with all my armature/constraint setups.

> In #48234#371151, @mont29 wrote: > This is a threading issue (running Blender mono-threaded, with `-t 1` command line option, shows no problem). Ah, thanks. Can confirm that `-t 1` fixes the issue with all my armature/constraint setups.

Campbell Barton commented

2016-06-03 10:25:51 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2016-06-03 10:25:51 +02:00

We could move away from using FCurve.curval.
This patch fixes the bug for me: P364

... just makes some local changes to avoid using FCurve.curval.

We could move away from using `FCurve.curval`. This patch fixes the bug for me: [P364](https://archive.blender.org/developer/P364.txt) ... just makes some local changes to avoid using FCurve.curval.

blender-admin commented

2016-06-03 16:57:44 +02:00

This issue was referenced by c6cc599311

This issue was referenced by c6cc5993118965ae4208d748c54e7a70a3c5c1d3

Campbell Barton commented

2016-06-03 16:57:56 +02:00

Changed status from 'Open' to: 'Resolved'

Campbell Barton closed this issue

2016-06-03 16:57:56 +02:00

Paul R commented

2016-06-15 15:04:57 +02:00

It's now working as expected. Thanks for the fix!

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Bone Action Constraints with shared Action leads to glitches #48234