[x3d-public] gltf for Humanoid loa4 level 1

[John Carlson]

I found this:
https://github.khronos.org/glTF-Tutorials/gltfTutorial/gltfTutorial_006_SimpleAnimation.html

How does it relate to HAnim?

John

On Tue, Jul 30, 2024 at 9:00 PM John Carlson <yottzumm at gmail.com> wrote:

> Sorry Joe, I really have difficulty looking at anything that’s not email,
> API, VRML, XML, JSON or program code.
>
> I don’t see how the JSON examples you link help me understand.  Do you
> have a full JSON animation example?
>
> On Tue, Jul 30, 2024 at 7:42 PM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
>> > Perhaps a next step is to provide an HAnim to glTF mapping.
>>
>>
>>
>> that is what I am talking about. Please take a look at the gltf tutorial
>> link and see what you think.
>>
>> It is easy to see that the gltf asset file(s) can be created from x3d
>> content and that gltf ascii can be created with text editor.
>>
>>
>>
>> All Best,
>>
>> Joe
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: John Carlson <yottzumm at gmail.com>
>> Sent: Jul 30, 2024 5:29 PM
>> To: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>
>> Cc: Joe D Williams <joedwil at earthlink.net>, <hanim at web3d.org>, <
>> x3d-ecosystem at web3d.org>
>> Subject: Re: [x3d-public] gltf for Humanoid loa4 level 1
>>
>>
>> Joe, we’ve discussed how Blender conversions of animation in X3D to glTF
>> get played in various X3D browsers.  Feel free to import as VRM [ sic ] and
>> export as glTF.  Feel free to import as BVH and export as glTF.
>>
>> Vince has tried to get X3D meshes converted to glTF with a stylesheet.
>>
>> We’re kind of waiting on the folks who do conversions from X3D to STL to
>> produce X3D to glTF.  Triangles and transforms are not an HAnim solution.
>>
>> Using the OOTB blender x3d importer is a non-starter since it doesn’t
>> import HAnim.  This might change, but I’m not seeing Blender people wanting
>> to help with X3D.
>>
>> There may be other Blender importers.
>>
>> There may be online X3D to glTF converters.
>>
>> glTF interactivity extension may be right around the corner.
>>
>> Perhaps a next step is to provide an HAnim to glTF mapping.
>>
>> On Tue, Jul 30, 2024 at 6:57 PM Joe D Williams via x3d-public <
>> x3d-public at web3d.org> wrote:
>>
>>>
>>>
>>> https://github.khronos.org/glTF-Tutorials/gltfTutorial/gltfTutorial_002_BasicGltfStructure.html
>>>
>>> gives some example tutorials with some user code. Even shows skinning
>>> with a simple set of rotation transforms.
>>> At least gltf is down to it and doesn't mind calling a joint a joint as
>>> the primary animation driver.
>>>
>>> Image 2a: The glTF JSON structure
>>>
>>> and following summary of elements text shows x3d we have everything
>>> needed to transcode hanim skeleton(s), geometries, and animations from x3d
>>> hanim to gltf and back. Well, not quite transcoding, because some level of
>>> relatively simple computational text name and value transformations might
>>> be needed to match x3d native xml nodes and fields to native gltf node and
>>> field names and content.
>>>
>>> This is to be expected, because x3d hanim nodes and fields and SAI are
>>> meant to be best authortime in terms of basic human-readable syntax,
>>> hierarchies, data stuffing, and realtime event processing, while the gltf
>>> has no 'runtime' or event system of any kind that I have seen. So our gltf
>>> oriented more toward the idea that the x3d hanim authortime has made it
>>> possible to simply reorganize or even precompute gltf data structures and
>>> elements for best transport and to optimize realtime delivery by the
>>> expected host runtime.
>>> Or, even transport to another gltf or x3d authortime.
>>> In fact the interchangability of using basic standard native gltf assets
>>> integrated with x3d native assets in a 'live' x3d authortime is handled
>>> just fine using standard x3d SAI.
>>>
>>> Image 2b: The glTF structure
>>>
>>> Gives a bit more detail about how a set of assets, even a single file of
>>> multiple embedded or in local or remote files of assets can be documented.
>>> Again, the basic is the 'scene' and it is composed of strongly typed but
>>> very versatile nodes and fields, some represented as buffers that appear to
>>> have few default definitions, but can be derived by the x3d definition of
>>> its SF form and content. So, for a gltf source collection of names and
>>> data, by the time it gets to the gltf it better be ready to execute without
>>> much ado. That is why x3d xml schema validation of the original input can
>>> be important and that comparable schema validation for the gltf json form
>>> be developed to the same degree.
>>>
>>> On and on through the tutorial and we see that like I said, there appear
>>> to be few defaults, like gltf may not be aware or types like MFvect3F, you
>>> must tell the name and parameter and how to interpret and access the data
>>> structure for every element. However, we are happy to see some familiar
>>> names for things like skin and joints
>>>
>>> Not to worry because the x3d native data, or data the live browser
>>> runtime would have to compute anyway for data is very well known and
>>> literally every standardized gltf asset definition is covered by x3d node
>>> and data types.
>>>
>>> Has anyone tried a conversion of an example hanim model into a single or
>>> set of gltf asset files?
>>> Attached is most simple loa4 with small geometry and basically just the
>>> skeleton Joint, Segment, Site nodes and measurements.
>>> We need an loa4 because lower loas can be easily found by reduction.
>>>
>>> The top reason for HAnim is transportable animations. The gltf can
>>> accommodate and even accelerate this good thing. It providing a very
>>> condensed form for a 'standard' skeleton hierarchy with realistic and
>>> custom dimensions then import realistic 'standard' and custom animations
>>> (learn unit quaternions, not hard just something about cosines and half
>>> angles and square roots?) along with geometry and behaviour accessories
>>> faster and easier and more reliably for interactive operations in a
>>> 'standard' time and event-driven virtualized environment.
>>>
>>>
>>> please note: "The local transform matrix always has to be computed as M
>>> = T * R * S."
>>> also see:
>>> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/components/grouping.html#Transform
>>>
>>> If you want to know about x3d hanim Displacers, check out gltf sparse
>>> accessors.
>>>
>>>
>>> https://github.khronos.org/glTF-Tutorials/gltfTutorial/gltfTutorial_007_Animations.html
>>>
>>> Some artifacts move around using the basic stuff of x3d. True, it is
>>> like gltf is made for convenient use by x3d and www.
>>> Because it is.
>>>
>>> Thanks and Best,
>>> Joe
>>>
>>>
>>>
>>> . le
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>>>
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>>
>>
>>
>
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