Multiple actions in Blender exporter broken

[daniel-nth]

7812b25 broke the export of multiple actions for me. Instead, only the currently active animation of an armature will be exported.
Isn't looping over data.actions and then checking for each action if it is identical to armature.animation_data.action the same as just exporting armature.animation_data.action in the first place?

[mrdoob]

/ping @bhouston

[bhouston]

/ping @jackcaron

[jackcaron]

@daniel-nth
data.actions holds every action in the scene, just like data.objects holds every objects. So using only actions relevant to this armature seems to be right approach.

But if you can provide me with a simpler Blender file that can reproduce this bug, I would like to look at it and see how I could fix this.

[antont]

we've used this model to test blender -> three.js exports, including multiple skeleton animations:
https://github.com/realXtend/chesapeakebay/blob/master/objects/White_Tailed_Deer/White_Tail_Deer_all.blend

that file has multiple actions / animations for the same armature / skeleton -- just mentioning in case if is helpful for you. we exported it succesfully with the old r6* era three.js and the old exporter and got it pretty much figured for current too with the help of nice people in the other issues about the blender exporter.

IIRC in that file they are as actions normally but also put to the sequencer timeline as those blends were originally authored for Ogre 3D and for an exporter with which you had put the actions you wanna export to the sequencer timeline one after another .. it also stepped through the anims as part of the export, perhaps to bake modifiers or something? This old exporter: https://code.google.com/p/blender2ogre/ . Interestingly enough the last commit it says "Extended the node animation script to support action user retrieval by NLA."

i don't remember exactly how it goes with multiple anims and the blender export now, should check more still too.

[daniel-nth]

@antont Thanks! With the current exporter I get zero animations in the exported JSON. When reverting 7812b25, I get three. When I link an animation in the action editor, that one action gets exported.

@jackcaron Thanks for looking into it!
I committed a simple test file that we made for animation testing a while ago over here: https://github.com/daniel-nth/three.js-issue-7631. The behaviour is the same as with the deer, only a linked animation gets exported. Neither me nor our Blender guy know a way to link more than one animation to an armature in the action editor.

[satori99]

@daniel-nth

I am fairly certain that Blender actions are completely decoupled from armatures they may act apon.
Any action can be applied to any armature, and if the action group names match any bone names, they will be animated by the action data.

I have 'solved' this in a blender script by checking each actions' group names against armature deform bone name. I deem an action as applicable to an armature object if the action does not contain any groups which don't correspond to armature bones.

Something like this

It's not bullet-proof but it works well enough if your armature bone names are descriptive and not simply 'Bone, Bone.001, ...'.

Unfortunately, I don't know enough about the current exporter addon code to know if/how/where this could be applied.

[bhouston]

So just to clarify, the reason we did this was because if you had multiple rigged characters in a scene, like a dog, a person and a robot, the exporter would export every animation for every character. Thus if there was 3 dogs animations, 1 person animation and 2 robot animation, the export would give the dog 6 animations, 3 of which were not his, the person 6 animations, 5 of which were not his, and the robot 6 animations, 4 of which were not his.

The current solution though clearly is exporting not enough, but the previous solution exported too many improper duplicates.

I guess one can undo our change until we get proper filtering.

[bhouston]

@daniel-nth if you wanted to make a PR with your fix, I think that would be a good idea. Sorry for the trouble.

[daniel-nth]

@bhouston Thanks! PR is on the way.

[mrdoob]

#7666