[x3d-public] What is "loa" ?

Sat Jun 20 13:22:36 PDT 2020

Hypothesis: the hanim motion fields were originally designed to make it
easy to copy and paste from freely available motion capture .bvh files.
If so, then -as we get further from copy and pasta-ability- there may be
some demand for tools to import .bvh and convert to these x3d MF fields.
Or - have web3d browsers load .bvh directly, via a mapping / lookup node /
field./ table which you would likely also need for import tools.
-Doug

On Sat, Jun 20, 2020 at 12:38 PM GPU Group <gpugroup at gmail.com> wrote:

>
> https://www.web3d.org/documents/specifications/19774/V2.0/MotionDataAnimation/ExampleMocapAnimationMotionObject.html
>
> This version of AnnexD is what I used - and it looks like an SFString 0 as
> does values and jpints
> WARNING - any examples from this AnnexD may need rework for web3d
> -Doug
>
>
> On Sat, Jun 20, 2020 at 12:21 PM Don Brutzman <brutzman at nps.edu> wrote:
>
>> MUFTI you definitely want to be looking at the HAnim2 specifications.
>>
>> Web3D Consortium members are the controlling authority for X3D and HAnim
>> specifications, International Standards Organization (ISO) certifies.
>>
>> X3D3 is simply implementing HAnim2, typically as tersely as possible so
>> that there is no confusion in prose that HAnim2 is the controlling
>> specification.  Please see
>>
>> * ISO/IEC 19774-1, HAnim2 Specifications parts 1 and 2
>>    https://www.web3d.org/documents/specifications/19774/V2.0/
>>
>> ===============================================
>> * ISO/IEC 19774-1, HAnim2 Specifications part 1
>>    clause 3 Terms and definitions
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/glossary.html
>>
>> 3.11
>>    level of articulation
>>    LOA
>>    degree of fidelity based on number of joints in an HAnim figure
>> ===============================================
>>
>> also
>>
>> * 4.8.5 Levels of articulation
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/concepts.html#LevelsOfArticulation
>>
>> "Level of articulation (LOA) represents the complexity and detail of
>> joints for a humanoid skeletal hierarchy, and can be used for generating
>> various motions based on the joints. There are five levels of articulation:
>>
>>      LOA‑0 represents only the humanoid_root Joint object without an
>> accompanying hierarchy, as shown in (Figure 4.3).
>>      LOA‑1 represents the simplest organization and hierarchy of joints
>> for a humanoid. There are 18 joints and 18 segments. Each segment has a
>> joint in the hierarchy. Figure 4.4 represents LOA‑1 joints.
>>      LOA‑2 consists of 71 joints and 71 segments (Figure 4.5).
>>      LOA‑3 consists of 94 joints and 94 segments (Figure 4.6).
>>      LOA‑4 builds on LOA‑3 by adding anatomical details of hands and feet
>> (Figure 4.7). LOA‑4 consists of 148 joints and 148 segments. Hands and feet
>> joints for LOA‑4 are illustrated in 4.9.3 and 4.9.4 respectively."
>>
>>
>> * 4.9 Structure of a humanoid, 4.9.6 Hierarchy
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/concepts.html#Hierarchy
>>
>> * 4.9 Structure of a humanoid
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/concepts.html
>>
>> * Annex A (informative) Nominal human body dimensions and levels of
>> articulation (LOAs)
>>    Nominal human body dimensions and levels of articulation (LOAs)
>>
>> * A.2 Levels of articulation (LOAs)
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/BodyDimensionsAndLOAs.html#LevelsOfArticulation
>>
>> There is a lot of information in there that deserves careful reading.
>> You will find tables and diagrams that illustrate every joint and (bone)
>> segment in the human body, along with a number of useful feature-point
>> sites.  This took years of effort by many members of HAnim working group.
>>
>> Current work by Joe Williams, John Carlson and myself is improving
>> past-legacy examples to match HAnim2 capabilities with X3D4.  We hope that
>> testing and verification will help.
>>
>> * HumanoidAnimation X3D Examples Archive
>>    https://www.web3d.org/x3d/content/examples/HumanoidAnimation
>>
>> * X3D Tooltips, HAnimHumanoid loa
>>    https://www.web3d.org/x3d/content/X3dTooltips.html#HAnimHumanoid.loa
>>
>> HAnim designers hope that by identifying both HAnimHumanoid models and
>> HAnimMotion animations with the LOA supported, it will be easier to
>> mix/match models and animations.  Since each LOA is a strict subset of the
>> next LOA, some compatibility is possible across human LOA levels.
>>
>> * 4.9.7 Site and Segment relationships
>>
>> https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/concepts.html#SiteSegmentRelationships
>>
>> It is not impossible to think that someday this work might even rise to
>> the level of rigor needed for 3D HAnim models becoming part of medical
>> records.  HAnim and X3D4 have the potential to help... everyone.
>>
>> Thanks for your scrutiny and helpful questions.
>>
>>
>> On 6/18/2020 11:02 PM, John Carlson wrote:
>> >
>> > To answer your question, many parts of the government like to create
>> acronyms.
>> >
>> > John
>>
>> Sorry John, can't blame government for this one.  (Wondering, are parts
>> of the government controlling your keyboard?!)
>>
>> > On Fri, Jun 19, 2020 at 12:38 AM J. Scheurich <mufti11 at web.de <mailto:
>> mufti11 at web.de>> wrote:
>> >
>> >     hI,
>> >
>> >     From
>> >
>> >
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD1/Part01/components/hanim.html#HAnimMotion
>> >
>> >     SFInt32 [in,out] loa -1 [-1,4]
>> >
>> >     What does "loa" mean ? Fieldnames in X3D are often english words,
>> >     but the dictionary leo.org <http://leo.org> has no results for
>> "loa" 8-(
>> >
>> >     so long
>> >     MUFTI
>> 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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>
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