How to clone a Skinned Mesh? - animation

Question

I need to have multiple identical, animated models on a scene. If possible, I would like them to have a shared geometry and material, but if it is impossible, having them instanced per model will suffice too.
Unfortunately, the only way to achieve this result I found is to go through JSONLoader for every model instance.
SkinnedMesh does have a clone() method, but it seems not to be fully implemented yet. If used and both original and cloned mesh are present on the scene, only one will appear, and cloned one will be without animation.
I have attempted to use this example with shared skeletons:
https://github.com/mrdoob/three.js/pull/11666
...and indeed it works, but I need to be able to play different animations for every model instance, having them all play the same one is not sufficient, sadly. I hoped I could do similar hax and insert my own skeleton (made out of bones from the JSON file), but it behaves very much like if I just used clone() from SkinnedMesh.
I am using this code:
https://github.com/arturitu/threejs-animation-workflow/blob/master/js/main.js
Basically what I'd like to achieve is
var onLoad = function (geometry, materials) {
window.geometry = geometry;
character = new THREE.SkinnedMesh(
geometry,
new THREE.MeshFaceMaterial(materials)
);
character2 = character.someMagicalClone();
scene.add(character);
scene.add(character2);
(...)
I need any clue... and while I wait for help, I am busily deconstructing constructor for SkinnedMesh and JSONLoader for clues ;)
Thanks in advance!

Answer 1

I found a solution in this pull request:
https://github.com/mrdoob/three.js/pull/14494
in short, there are two functions added:
function cloneAnimated( source ) {
var cloneLookup = new Map();
var clone = source.clone();
parallelTraverse( source, clone, function ( sourceNode, clonedNode ) {
cloneLookup.set( sourceNode, clonedNode );
} );
source.traverse( function ( sourceMesh ) {
if ( ! sourceMesh.isSkinnedMesh ) return;
var sourceBones = sourceMesh.skeleton.bones;
var clonedMesh = cloneLookup.get( sourceMesh );
clonedMesh.skeleton = sourceMesh.skeleton.clone();
clonedMesh.skeleton.bones = sourceBones.map( function ( sourceBone ) {
if ( ! cloneLookup.has( sourceBone ) ) {
throw new Error( 'THREE.AnimationUtils: Required bones are not descendants of the given object.' );
}
return cloneLookup.get( sourceBone );
} );
clonedMesh.bind( clonedMesh.skeleton, sourceMesh.bindMatrix );
} );
return clone;
}
function parallelTraverse( a, b, callback ) {
callback( a, b );
for ( var i = 0; i < a.children.length; i ++ ) {
parallelTraverse( a.children[ i ], b.children[ i ], callback );
}
}
As I understand it rebinds cloned skeleton to the cloned mesh.
so topic example could look like:
var onLoad = function (geometry, materials) {
window.geometry = geometry;
character = new THREE.SkinnedMesh(
geometry,
new THREE.MeshFaceMaterial(materials)
);
character2 = cloneAnimated(character); // <-- used that new function
scene.add(character);
scene.add(character2);
(...)