Dynamic bones animation in Three.js

Question

Is it possible to create a dynamic animation by applying transformations to the bones of a 3D model using three.js? I tried moving and rotating the bones of a SkinnedMesh, but the mesh was not updated.

        loader = new THREE.JSONLoader();
        loader.load('/JS-Projects/Virtual-Jonah/Modelos/initialPose.js',function jsonReady( geometry )
        {
            mesh = new THREE.SkinnedMesh( geometry, new THREE.MeshNormalMaterial({skinning : true}) );
            mesh.scale.set( 10, 10, 10 );
            mesh.position.z = mesh.position.y = mesh.position.x = 0;
            mesh.geometry.dynamic = true;
            scene.add( mesh );

            var index = 0;
            for (var i = 0; i < mesh.bones.length; i++)
            {
                if (mesh.bones[i].name == "forearm_R")
                {
                    index = i;
                    break;
                }
            }


            setInterval (function ()
            {
                mesh.bones[index].useQuaternion = false;
                mesh.bones[index].position.z += 10;     
                mesh.bones[index].matrixAutoUpdate = true;
                mesh.bones[index].matrixWorldNeedsUpdate = true;
                mesh.geometry.verticesNeedUpdate = true;
                mesh.geometry.normalsNeedUpdate = true;

                renderer.render(scene, camera);
            }, 33);

            renderer.render(scene, camera);
        });

The model I am using was created with makeHuman (nightly build), exported to Collada, imported in Blender and exported to the three.js JSON model. The link to the model is the following:

https://www.dropbox.com/sh/x1606vnaoghes1y/gG_BcZcEKd/initial

Thank you!

Answer 1

Yes, you can! You need to set mesh.skeleton.bones[i], both mesh.skeleton.bones[i].rotation and mesh.skeleton.bones[i].position. Rotation is of type Euler. Position is of type Vector3. I have actually tested this using my code from here https://github.com/lucasdealmeidasm/three-mm3d (that includes a working skinned mesh with bone-attachable objects) and one can indeed do that.

Note that Inateno's answer is very wrong, there are many instances where this is necessary. For example, in a FPS, one uses both dynamic and non-dynamic animation. When a character runs and holds a gun, the direction he points the gun at is dynamically set (one could use mesh.skeleton.bones[i].rotation where "i" is the index for bone assigned to the arm for that) while the rest of the animation, including the walking, is made in the editor and loaded. One can, in three.js, use "THREE.AnimationHandler.update(delta);" and then change single bones' position and rotation in code to solve those issues.

Answer 2

I know you can export a bone driven animation from Blender in JSON format, for use in THREE.js, there are a few tutorials of that around the web. I hope this helps. Good Luck.

Answer 3

If I understund you want to create animations yourself inside the code ? You are note supposed to do this, in Unity you have a simple animation editor, you never manipulate bones directly in code.

It's long, boring, unperforming. To animate a model use animation directly. Here's a result of animation with some bones manipulation but there is an animation over.

http://threejs.org/examples/webgl_animation_skinning_morph.html

Here is a tutorial about making simple animation if you need http://blog.romanliutikov.com/post/60461559240/rigging-and-skeletal-animation-in-three-js

And here a related post about animations problems just in case Blender exports a three.js animation - bones rotate strangely

Hope this will help you :)