Armature Circular Dependancy #67224

New Issue

Erik · 2019-07-19T13:18:12+02:00

Erik commented

2019-07-19 13:18:12 +02:00

System Information
Operating system: Windows 10
Graphics card: GTX 980Ti

Blender Version
Broken: 2.80 Release Candidate, 19.07.2019
Worked: 2.79

Short description of error
I sometimes apply simple soft body effects on an armature via another object for performance reasons, often by using a Curve. It's very helpful to get sufficient movement of hairstrands, wings, clothes or whatever, while also maintaining the option of manual animation.

The setup is structured as follows:
Soft body object (Curve) is parented to a (Root) Bone -> Simulated soft body shape determines position of an Empty -> Another bone in the same armature copies the location of the Empty and achieves the deformation

Pure guessing
Surprisingly enough, in 2.79 this worked marveliously, eventhough there's kind of a circular dependancy involved if the armature is considered one object (Bone1 Location -> Curve and Empty -> Bone2 Location ). I'm not a good programmer and far from understanding dependancy issues in blender but my guess is, that bones in one Armature are treated in one run now, whereas in 2.79 there must have been a distinction of bones having external dependancies, so they were updated only after their target?!

Bad workaround
It's possible to split up the armature in two. In this case, it seems to work fine. Sadly, it would be a lot of work for me to do, less convenient to work with and sometimes even messes up my weight painting.

Exact steps for others to reproduce the error
Open the test file and start animation playback. In 2.79 everything works fine, in 2.8 glitching occurs.

test.blend

**System Information** Operating system: Windows 10 Graphics card: GTX 980Ti **Blender Version** Broken: 2.80 Release Candidate, 19.07.2019 Worked: 2.79 **Short description of error** I sometimes apply simple soft body effects on an armature via another object for performance reasons, often by using a Curve. It's very helpful to get sufficient movement of hairstrands, wings, clothes or whatever, while also maintaining the option of manual animation. The setup is structured as follows: Soft body object (Curve) is parented to a (Root) Bone -> Simulated soft body shape determines position of an Empty -> Another bone in the same armature copies the location of the Empty and achieves the deformation **Pure guessing** Surprisingly enough, in 2.79 this worked marveliously, eventhough there's kind of a circular dependancy involved if the armature is considered one object (Bone1 Location -> Curve and Empty -> Bone2 Location ). I'm not a good programmer and far from understanding dependancy issues in blender but my guess is, that bones in one Armature are treated in one run now, whereas in 2.79 there must have been a distinction of bones having external dependancies, so they were updated only after their target?! **Bad workaround** It's possible to split up the armature in two. In this case, it seems to work fine. Sadly, it would be a lot of work for me to do, less convenient to work with and sometimes even messes up my weight painting. **Exact steps for others to reproduce the error** Open the test file and start animation playback. In 2.79 everything works fine, in 2.8 glitching occurs. [test.blend](https://archive.blender.org/developer/F7618079/test.blend)

Erik commented

2019-07-19 13:18:12 +02:00

Added subscriber: @ElrikLeBaum