Attachment Nodes not updated after changing Armature's bind pose

[yaRnMcDonuts]

When a model's bones are adjusted and saved by calling armature.saveBindPose(), the attachment nodes do not get updated.

More information and a screenshot showing the issue in this thread: https://hub.jmonkeyengine.org/t/attachmentnodes-are-not-updated-after-armatures-bind-pose-is-updated/47995

[stephengold]

Is this a recent regression? I haven't checked, but I wouldn't be at all surprised if this issue existed all the way back to JME 3.3.

[yaRnMcDonuts]

I experienced this issue on 3.7, although I had never tried calling .saveBindPose() on any older version to know for sure if it ever worked.

But in my search for a solution, I did not manage to find any old posts or reports from any jme devs that have ever managed to modify and save a bind pose successfully, so my best guess would be that this issue has been around since 3.3 when the new animation system was added.

[stephengold]

saveBindPose() is invoked every time you use AnimMigrationUtils to convert an animated model from the old animation system to the new one.

Aside from that, I'm not aware of any use cases for it. Typically the bind pose is generated by a modelling tool such as Blender.

[yaRnMcDonuts]

I was planning to call saveBindPose() to update the bind pose after translating a model's leg and arm jointts, for the purpose of dynamically scaling a model's height at run time, so that a single character model can be edited to be any height.

The distortion issue also does not occur immediately upon calling the saveBindPose() method. It only becomes apparent after the method gets called many times.

I actually only noticed the distortion issue after I began calling the saveBindPose() method every frame when I connected the call to a listener for a Slider in the gui.

So it is likely that AnimMigrationUtils does not encounter the distortion issues since it only calls the method once.

And AnimMigrationUtils also manages to side-step this attachment node issue because the attachmentNodes will all be in the same place before and after it converts the model and calls the saveBindPose() method, since none of the bones are scaled or translated by AnimMigrationUtils

[stephengold]

Perhaps there's a bug here, or perhaps your application requires a different algorithm. Without a thorough investigation, I can't tell.