[x3d-public] Can you get this X3D animation imported into Blender?

[John Carlson]

Sorry TL;DR.  Major point:  both Blender bones and Skeleton as Transforms
should be supported for maximum flexibility.  What are your thoughts?

Replying to Joe:

Understood.  AFAIK, I still need blender bones to export weights right now,
but Blender bones only provide for Joints, not segments or sites (can I
attach EMPTYs to Blender bones in a particular  mode?).  I will experiment
with attaching weights to EMPTYs (joints),  then on export, I will move
weight detection from Blender bones to EMPTYs,  we can do limited mapping
on export, but asking someone to map an entire LOA4 skeleton is
unrealistic. I don’t even like LOA1-LOA2 in VRM and BVH. Such
user-specified mapping should be saved for reuse.  I can already do MoMask
BVH joint mapping on export (but not “End Site” yet).  We probably won’t be
able to save HAnim  to VRM skeletons, and I think that USDSkel may do
armature/bones as well, so I’m not seeing X3D to USD Skel particularly
working.  *I think Doug suggested a separate skeleton mapping app*, perhaps
this feasible.  It’s just not realistic with glTF files exported to
8GB-14GB X3D files 200 times the size of a Blender file.

The good news is, I got small Transform hierarchies import mostly working
in Blender with matrix_local and translation. Now to follow through with
centers and HAnim.  Moving like molasses, but with simple examples, things
are easier and moving faster without waiting years for import and tons of
logging.

*Katy can comment on rigging and armature in Blender, *as what might be
missing if we don’t import Blender bones,  this may severely impact the
apparel workflow in Blender.

*Most likely, both paths should be supported.*  I hope you are in
agreement.  Perhaps separating out the import/export into separate addons
would make decisions easier.

Your additional thoughts are welcome.

On Thu, Jun 6, 2024 at 2:48 PM Joe D Williams <joedwil at earthlink.net> wrote:

> > Can we use the same transform code in Blender for both Transform and
> HAnim?
>
>
>
> Yes, if blender transform operation can use 'center', which Joint needs.
> Just name the objects so the Humanoid, Joint, Segment, Site transforms can
> be transcoded at export into into HAnim hierarchy.
>
> Joe
>
>
>
>
>
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>
> -----Original Message-----
> From: John Carlson <yottzumm at gmail.com>
> Sent: Jun 6, 2024 5:03 AM
> To: Joe D Williams <joedwil at earthlink.net>
> Cc: Katy Schildmeyer KS APPAREL DESIGN <katy at ksappareldesign.com>, X3D
> Graphics public mailing list <x3d-public at web3d.org>
> Subject: Re: Can you get this X3D animation imported into Blender?
>
>
> Okay, Joe.  Now to get this working in Blender, since you’ve confirmed the
> behavior.  Thanks!
>
> Can we use the same transform code in Blender for both Transform and HAnim?
>
> John
>
> On Thu, Jun 6, 2024 at 5:35 AM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
>> Hi John,
>>
>>
>>
>> You sent this:
>>
>>
>>
>>   <Transform DEF="TransformRoot1" center="0 0 0">
>>     <Shape>
>>       <Box size='0.5 0.5 0.5'/>
>>     </Shape>
>>     <Transform DEF="TransformTargetParent1" center="4 0 0">
>>       <Shape>
>>         <Box size='0.5 0.5 0.5'/>
>>       </Shape>
>>       <Transform DEF="TransformTargetChild1" center="8 0 0">
>>         <Shape>
>>           <Box size='0.5 0.5 0.5'/>
>>         </Shape>
>>       </Transform>
>>     </Transform>
>>   </Transform>
>>
>>
>>
>> Not shown here is the interpolator that sends rotations to both Parent
>> and Child Transforms
>>
>> For this animation code you sent this did exactly what it should have
>> done.
>>
>> The boxes start at 0 0 0 then are swept along the axis according to the
>> Parent and Child Transform nodes animation input.
>>
>> Note that the initial position of all three boxes is 0 0 0, then they
>> move along the radius from where you set the parent centers.
>>
>>
>>
>> Please have a look at this:
>>
>>
>>
>> First, slight change from what you sent.
>>
>> Again, a important understanding is that "center" value of the Transform
>> represents the center of rotation of that Transform, and may have nothing
>> much to do with the value for translation, which is 0 0 0 for the parent
>> Transform for each Shape.
>>
>>
>>
>>   <Transform DEF="CenterRoot1" center="0 0 0">
>>     <Shape>
>>       <Box size='0.5 0.5 0.5'/>
>>     </Shape>
>>     <Transform DEF="CenterParent1" center="4 0 0">
>>       <Shape>
>>         <Box size='0.5 0.5 0.5'/>
>>       </Shape>
>>       <Transform DEF="CenterChild1" center="8 0 0">
>>         <Shape>
>>           <Box size='0.5 0.5 0.5'/>
>>         </Shape>
>>       </Transform>
>>     </Transform>
>>   </Transform>
>>
>>
>>
>> So again, all Shapes start at 0 0 0 then are swept through the arc
>> defined by each parent Transform center.
>>
>>
>>
>> This version operates like the hanim model.
>>
>> The parent Transform is a "Joint" with center defined, then the Shape has
>> its own Transform to place it at the parent center value.
>>
>> (The first center="0 2 0" translation='0 2 0' just moves the is example
>> up above the first example.)
>>
>>
>>
>>   <Transform DEF="TransformRoot2" center="0 2 0" translation='0 2 0'>
>>     <Transform DEF="MoveToCenterRoot" translation="0 2 0">
>>       <Shape>
>>         <Box size='0.5 0.5 0.5'/>
>>       </Shape>
>>     </Transform>
>>     <Transform DEF="CenterTargetParent2" center="4 0 0">
>>       <Transform DEF="TranslateTargetParent2" translation="4 0 0">
>>         <Shape>
>>           <Box size='0.5 0.5 0.5'/>
>>         </Shape>
>>       </Transform>
>>       <Transform DEF="CenterTargetChild2" center="8 0 0">
>>         <Transform DEF="TranslateTargetChild2" translation="8 0 0">
>>           <Shape>
>>             <Box size='0.5 0.5 0.5'/>
>>           </Shape>
>>         </Transform>
>>       </Transform>
>>     </Transform>
>>   </Transform>
>>
>>
>>
>> In Humanoid space, once the connection between using center to set the
>> Joint center of rotation and then a child Transform to position any
>> associated stuff in Humanoid space just makes it work wonderful for what we
>> need in hanim.
>>
>>
>>
>> I can recall a day when there were sincere discussions over whether to
>> include the 'center' field in Transform.
>>
>>
>>
>> Thanks,
>>
>> Joe
>>
>>
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