[x3d-public] [h-anim] Basic Animataion data

doug sanden highaspirations at hotmail.com
Fri Nov 11 12:18:19 PST 2016

> > Looks good - quats.
> > -Doug
> > ..
> > And I think if dropping general transform -with scales- for joints,
> > that means if you have skinNormals, you do the same transform on
> > normals (as coords) instead of inverse-transpose, which IIRC
> > corrects for anisotropic-scale-induced shear.
> That sounds big. I think you would need to write a fairly complete
> outline on what to change.

No spec changes needed - just internal code. If your joints nave no an-isotropic scales then in theory you can skip one inverse per joint transform. 

> Put this in as a spec comment. I have one in there that asks for
> inclusion of either axis-angle of unit quaterions.
> Of course the main issue, is that as far as I know, collada and glTF
> will only use unit quats for animation sequence transposrt.
> > ...
> > freewrl converts axis angles to quats internally for some things
> > already - to avoid the pole singularity with axis angles.
> Great, now will you implement the HAnim stuffs.


> > ...
> > Would like to see more goodies in HAnim / Anim.
> > When implementing hanim in freewrl I was shocked by how little work
> > the web3d browser does, and how much work is left for the content
> > developer to do.
> Notice that the Joint node does have fields for data to do IK, so that
> a joint could be moved by other than hierarcal joint rotations. Just
> that as far as I know, those fields never got implemented but I guess
> with hope, the fields were left in the X3D spec. .
> > For example IK. Q. Should we have a general IK solver node? Or other
> > nodes to lighten the burden on content developers? Joe mentioned
> > something about assigning joint weights automatically. Is that a
> > node, or option in node?
> Sure, you look out there and see the IK in the tool, which really
> helpsif you are making ketframes, or tyrying to do a realistic
> simulation. You push a button and the thing gets rigged. Fantastic.
> Ihope you will see that all the basic stuff needed to fully document
> those items of interest are in the or can be added to, the HAnim.
> > ...
> > I'm not sure I understand the difference between maya and blender
> > when it comes to root nodes. Isn't that something an exporter could
> > add, if missing?
> Look at LOA0. All there is is root node. The root node navigates the
> position and orietation of the skeleton-space, within the Humanoid
> space.
> > ...
> > I might have time in 2017 to do blender exporter for hanim.
> DOes freewrl do hanim? Can you do the skinnng?

Yes. BoxMan.x3d. With displacers.

> > I saved the old campbell barton python x3d exporter, which I hacked
> > several ways before. Although it seems like a struggle to keep it
> > working in latest revisions of blender: plugin api was a moving
> > target for a while, didn't work last time I tried it:
> > https://sourceforge.net/p/freewrl/git/ci/develop/tree/freex3d/blender_scripts/
> >
> See what you can get and we can convert to X3D hanim.
> Warning, getting the skin bindings may be hard.
> All the joint (or bone) vertex vindings and weights may be locked up
> in a script (as I saw in Unity).
> In general, the bindings are the most carfully kept secret of the
> avatar.

OK I'll watch for that. Thanks Joe. The python export scripts are completely dependent on what the blender scripting API exposes. If it doesn't expose the rigging/joints then no export possible without hacking blender C code.
- it seems to have some Armature / Bone things exposed.

> Thanks,
> Joe

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