[X3D-Public] [X3D] H-Anim WG, higher LOA considerations

GLG info at 3dnetproductions.com
Thu Nov 14 00:35:38 PST 2013

I have worked with SolidWorks, which is capable of assisting with 3D
parametric modeling. Coordinates, rotation angles and translation data can
be kept in Excel spreadsheets, then interfaced with Visual Basic as a
scripting API to effect hierarchical movement as you described. It can only
export to VRML 1.0 (unless new export modules have become available) but
this is not what I am getting at.

I am mentioning the above first, because it could be a great tool for
experimenting and building the data sets and formulas that you are looking
for. But even if only for the methodology, keeping the animation data
separate from the objects, so that they may be re-used, makes sense. To that
effect, I am aware that a number of motion and gesture file formats are in
existence, some of which dealing more specifically with the skeleton. Since
similar work has already been done, some of which open source, hopefully you
can find more precisely what you are looking for.



-----Original Message-----
From: X3D-Public [mailto:x3d-public-bounces at web3d.org] On Behalf Of Don
Sent: Wednesday, November 13, 2013 10:55 PM
To: Myeong Won Lee; h-anim at web3d.org
Cc: Medical working group; X3D Graphics public mailing list
Subject: Re: [X3D-Public] [X3D] H-Anim WG, higher LOA considerations

[cc: Medical & x3d-public for possible anatomical expertise]

We are trying to build a better body and are trying to figure out how to go
from the current Level of Articulation (LOA) 0,1,2,3 out to the full
anatomically correct human skeleton.

Attached is a diagram leading from our discussion today... further informed
by Kwan Hee Yoo's work to model high-definition face, hands and feet as
H-Anim additions.

On 11/13/2013 6:28 PM, Don Brutzman wrote:
> a further design enhancement, hoping to capture the questions better...
> composability concern:  can different parts in different humans be
combined, perhaps merged at a single common joint?

if HAnimHumanoid node might begin by containing any HanimJoint, not just
sacrum, then different body parts might be composable at the shared
parent/child HanimJoint.

I've always assumed that the sacrum Joint had to be the root.  It would be
tedious (and not very composable) if each body part had to have a full
skeleton linking it back to sacrum every time.

We looked in the H-Anim specification and didn't find a specific prohibition
against other joints as the root...  could be there though. Joe might know.


"The skeleton field contains the HumanoidRoot Joint object.  The Humanoid
object is considered the parent object of the HumanoidRoot Joint object and
defines a coordinate space for the HumanoidRoot Joint object.  Thus, the
Humanoid object's transformation affects the Joint object hierarchy in the
skeleton field.  A hierarchy of Joint objects is defined for each H-Anim
humanoid figure within the skeleton field of the Humanoid object and a
hierarchical definition of joints is present even when the geometry of the
humanoid figure is not defined within the skeleton field."

Also found useful:




which does define the complete hierarchy, including

	HumanoidRoot : sacrum

Back to the diagram, going beyond the current limits of HAnim LOA 0 through

Dick insightfully observed that the dotted lines actually run back to the
center in this diagram.

it would be very interesting to take the an LOA3 figure and
- flatten it in 2D
- spread out the node tree radially into respective circles for each LOA,
since they are all strict subsets
- note what other other parts are still needed and where they go
- in essence, put sacrum at center of attached diagram and propagate the
skeleton graph outward across LOAs

Does anyone know of such a flattened skeleton, treating the joints
mathematically as a graph structure?

all the best, Don
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman

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