[x3d-public] HAnim joint center field

[Andreas Plesch]

The joint object is similar to a Transform node but its center field
is not relative to the parent (local) coordinate system but relative
to HAnim joint root node coordinate system which may be a grand parent
joint node, for example. See

http://www.web3d.org/documents/specifications/19774-1/V2.0/HAnim/ObjectInterfaces.html#Joint

4th paragraph:

'The center field specifies a translation offset from the root of the
overall humanoid body.'

This is in contrast to a regular Transform node where the center field
is relative to local coordinate system.

Most of the HAnim examples have a deeper Joint hierarchy, with
non-zero center fields.

Here is a set of working examples in x3dom:

https://rawgit.com/andreasplesch/x3dom/HAnim_work/test/functional/HAnim/inlineloader.html

This seems fine. However, x3dom here treats the Joint node almost
exactly like a Transform node, without any special treatment of the
center field. So, in theory, these examples should be rather messy
since all of the joint offsets should be incorrect.

So either the x3dom implementation is somehow accidentally doing the
right thing, or the example have center field values which are
relative to their local coordinate system.

I suppose, I could translate the simplest example, probably
DiamondManLOA0, to use Transform nodes in place of HAnimJoint nodes,
to test.

Could it be that the examples have HAnimJoint center field values
which are not strictly adhering to the spec. but rather follow the
Transform norm ?

Thanks,

-Andreas

-- 
Andreas Plesch
Waltham, MA 02453