[x3d-public] HAnimDisplacer effect on coord.point in Segments

[Joe D Williams]

https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/ObjectInterfaces.html#Displacer


" For the Displacer objects that are contained in the displacers field of the Segment objects, the displacements are defined and applied in the Segment coordinate system. The base mesh for the morphed Segment is the original mesh defined in the Segment.
For the Displacer objects that are contained in the displacers field of the Joint objects, the displacements are applied to the deformable mesh specified in the skinCoord field of the Humanoid object. The displacements are defined in the local coordinate system of the Joint object that contains the Displacer.
The weighted displacements shall be applied to the skinCoord array in the coordinate system of the Humanoid object. Therefore, the displacements shall be transformed from the Joint object space into the Humanoid object space. The base mesh for the morphed skin is the deformed mesh that results from the bone-based skin deformation. "

So, don't need anything extra field for Segment geometry but it seems that limits a
Segment to one geometry if displacer is used, although displacer in Segment
will probably work with index according to the order the points appear
in the coord points field(s) if multiple geometries in Segment. 

Overall that is the way the skin works. If skin is actually
composed of select points of various Segment geometries
instead of a single geometry, then the only the points in skinCoord
are actually animated,  

Thanks,
Joe


-----Original Message-----
From: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>
Sent: Feb 8, 2025 3:13 AM
To: X3D Graphics public mailing list <x3d-public at web3d.org>
Cc: Andreas Plesch <andreasplesch at gmail.com>
Subject: [x3d-public] HAnimDisplacer effect on coord.point

https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/components/hanim.html#HAnimDisplacer
 
does not directly explain what the effect of the displacer on the coord.point field of the containing HAnimSegment is. But it mentions the coord.point field and seems to imply that the coord.point field is involved.
 
So the question is if the Displacer should alter the coord.point field in order to achieve a graphical displacement, or if the Browser should only apply the displacements during rendering without a change in the coord.point field ?
 
This is relevant if the coord.point field is accessed by routes or scripts, in addition to displacers.
 
Thanks for any feedback or ideas,
 
Andreas
 
-- 
Andreas Plesch
Waltham, MA 02453





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