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

[Joe D Williams]

Humanoid, Joint, Segment, Site are all basic Transform nodes with some special fields added, but none of which are used in the Jin example.  
So, simple Joint nodes operate just like an ordinary Transform.
In general, there are no dimensions in Segment, but Joint holds a center value and  Site holds a translation value, all given as an 'offset' from 0 0 0. 

Notice that for Joint nodes, the default translation value of 0 0 0 is used everywhere and the center value gives the center of rotation for the Joint. The Site translation value positions the Site content as a child of its Joint and Segment so it moves properly relative to its parent.  

Thanks for the study, 
Joe
-----Original Message-----
From: John Carlson <yottzumm at gmail.com>
Sent: Jun 6, 2024 7:26 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?

It looks like the matrix multiplication in the Blender addon is correct per the standard for Transforms, looking up if HAnimJoints, etc. behave differently in the standard.

On Thu, Jun 6, 2024 at 7:03 AM John Carlson <yottzumm at gmail.com (mailto:yottzumm at gmail.com)> wrote:
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 (mailto: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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