[x3d-public] HAnim 2 X3DUOM...what is default?

[John Carlson]

My suggestion is to make X3DUOM more descriptive.   Can we put the
following into X3DUOM?

On Thu, Mar 25, 2021 at 6:53 PM Joseph D Williams <joedwil at earthlink.net>
wrote:

>
>    - … what the default value represents …
>
>
>
> SITES:
>
> Please look at part 1 annex B. The artwork illustrates the target
> locations for important surface features and reference measurement points
> of the humanoid. These are common body surface features used by a wide
> range of interchange. The tables in Part 1 Annex A lists a typical x y z
> location relative to 0 0 0 between the feet in the standard default pose.
> For hanim v2 we reused all v1 sites and added more from established work in
> other international humanoid interest groups. These human-scale
> measurements can be used to define a “standard” x3d hanim humanoid skin
> space.
>
>
>
> JOINTS:
>
> From this skin space, the v1 team estimated appropriate joint center
> locations for the skeleton and located them in the same coordinate system
> using the same human scale in order to generate the “standard” list of
> skeleton joint center locations shown in the table of Part 1 Annex A.
>
>
>
> TOGETHER:
>
> Combining the skin space and skeleton space models with some example
> animations then serves to completely validate the structure and function of
> the web3D x3d hanim character model. The humanoid can be built and animated
> in 5 levels of articulation to serve simple visual interactive transactions
> up to high fidelity kinematic simulations in immersive environments. And,
> since the x3d live scenegraph with internal/external SAI is the best, if
> not the best, realtime interactive data base, we have a great playground
> for hanim creations.
>
>
>
> So, to summarize, interested people made some progress from the mechanical
> armature to a programmable skeleton designed for interaction with other
> humanoids. They and us took the time to develop vrml and x3d until the
> hanim authortime can support human readable and highly transportable user
> code and a runtime that can use all of x3d and show the best of hanim
> versatility.
>
>
>
> Finally, now you can see that the skin space and skeleton space are
> distinct but stuffs gonna work best when the spaces are the same. Skeleton
> space is determined by the location of each Joint (itself an enhanced
> Transform node) center value. The effect of changing rotation value of a
> joint depends upon its function in the skeleton hierarchy.
>
> Likewise, the location of a surface feature also depends upon its position
> relative to 0 0 0 (can be considered in skin space but technically a style
> of user code can embed the Site location in Segment space).
>
>
>
> An example is if the skeleton is size fortyX relative to natural human
> space, then if you scale the skeleton to fit default scene space, and you
> have figured out how to do that with reasonable result, then you would set
> the Site locations in default scene coordinate space. If you did not
> rescale the skeleton natural human space, then the Sites would again be
> placed relative to skeleton space.
>
>
>
> Finally, the general recommendation for this is just draw the stuff in
> place relative to a “standard” humanoid using dimensions for your target
> character. If you have skeleton that is not dimensioned with respect to the
> natural scale, then change the joint centers to eliminate the need to
> somehow “scale the skeleton” to fit into a human-scale VR.
>
>
>
> I hope this helps to lead you further into the fun of hanim. (For example,
> notice the default value for every Joint translation is by default and just
> works out right to be 0 0 0. The joint center value determines how it
> produces an effect on the hierarchy. For the Site, its location is set
> directly by its parent Segment and moves according to the parent Segment.
> The skeleton hierarchy is in Humanoid space but to scale the skeleton you
> must scale the Humanoid. If you scale the Humanoid, then you are scaling
> every contained space.)
>
>
>
> Thanks and Best,
>
> Joe
>
>
>
>
>
>
>
>
>
> *From: *John Carlson <yottzumm at gmail.com>
> *Sent: *Wednesday, March 24, 2021 9:45 PM
> *To: *Don Brutzman <brutzman at nps.edu>; X3D Graphics public mailing list
> <x3d-public at web3d.org>
> *Subject: *[x3d-public] HAnim 2 X3DUOM...what is default?
>
>
>
> It would be most helpful if the default value in the enumerations in the
>
> HAnim concrete nodes in X3DUOM would some how inform the reader what the
>
> default attribute's value represents in the Humanoid (is it a center or
>
> translation for example).
>
>
>
> Thanks!
>
>
>
> John
>
>
>
>
>
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