[x3d-public] HAnimDisplacer effect on coord.point

Sun Feb 9 11:30:03 PST 2025

I think this is preferable.  The computation should be done in parallel or
SIMD.

On Sun, Feb 9, 2025 at 12:41 PM Holger Seelig via x3d-public <
x3d-public at web3d.org> wrote:

> X_ITE applies the HAnimDisplacers in the shader, thus no coord.point field
> has to be changed.
> Maybe that helps.
>
> Best regards,
> Holger
>
> --
> Holger Seelig
> Leipzig, Germany
>
> holger.seelig at yahoo.de
> https://create3000.github.io/x_ite/
>
> Am 09.02.2025 um 19:33 schrieb Andreas Plesch via x3d-public <
> x3d-public at web3d.org>:
>
> That would be the point field of a Coordinate node
>
>
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/rendering.html#Coordinate
>
> which is used by the coord field of
>
>
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/hanim.html#HAnimSegment
>
> Andreas
>
> On Sun, Feb 9, 2025, 12:36 PM Joe D Williams <joedwil at earthlink.net>
> wrote:
>
>> >  coord node emit a point_changed event
>>
>>
>> sorry,I don't see a field anywhere with that event. Displacer is likely
>> to change several points when new weight is sent. All part of the cascade
>> to produce the changed mesh?
>> Thanks,
>> Joe
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Andreas Plesch <andreasplesch at gmail.com>
>> Sent: Feb 9, 2025 4:25 AM
>> To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
>> Cc: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>,
>> Carol McDonald <cemd2 at comcast.net>, Joe D Williams <joedwil at earthlink.net>,
>> John Carlson <yottzumm at gmail.com>
>> Subject: Re: [x3d-public] HAnimDisplacer effect on coord.point
>>
>>
>> Don, Joe and John
>>
>> Thanks for collecting these references.
>>
>> But I am not sure if there is an answer to my original question. Let me
>> rephrase a bit the question:
>>
>> After a Displacer contained in a Segment node receives a set_weight
>> input, should then the coord node emit a point_changed event ?
>>
>> I do not think HAnim is concerned about that, so it is really a X3D
>> question.
>>
>> Thanks, Andreas
>>
>> On Sun, Feb 9, 2025, 12:49 AM Brutzman, Donald (Don) (CIV) <
>> brutzman at nps.edu> wrote:
>>
>>> Thanks for pointing in the right direction John.
>>>
>>> Direct links to functional requirements for Displacer in HAnim 2.0
>>> specification:
>>>
>>>    - HAnim 2.0. Part 1:  Humanoid animation (HAnim) architecture,
>>>    Clause 4 Concepts, 4.7 Displacer object
>>>    -
>>>    https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/concepts.html#DisplacerObject
>>>
>>>    - HAnim 2.0. Part 1:  Humanoid animation (HAnim) architecture,
>>>    Clause 6 Object interfaces, 6.6 Displacer
>>>    -
>>>    https://www.web3d.org/documents/specifications/19774/V2.0/Architecture/ObjectInterfaces.html#Displacer
>>>
>>> and
>>>
>>>    - X3D 4.0 Architecture, Clause 26 Humanoid Animation (HAnim)
>>>    component, 26.3.1 HAnimDisplacer
>>>    -
>>>    https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/hanim.html#HAnimDisplacer
>>>
>>> and informative
>>>
>>>    - X3D Tooltips, HAnimDisplacer
>>>    - https://www.web3d.org/x3d/content/X3dTooltips.html#HAnimDisplacer
>>>
>>> Thanks for implementation efforts and careful scrutiny.
>>>
>>> Questions and potential issues/clarifications/corrections are always
>>> welcome.
>>>
>>>
>>> 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
>>> https://faculty.nps.edu/brutzman
>>>
>>>
>>>
>>> ------------------------------
>>> *From:* x3d-public <x3d-public-bounces at web3d.org> on behalf of John
>>> Carlson via x3d-public <x3d-public at web3d.org>
>>> *Sent:* Saturday, February 8, 2025 3:43 AM
>>> *To:* Extensible 3D (X3D) Graphics public discussion <
>>> x3d-public at web3d.org>; Carol McDonald <cemd2 at comcast.net>; Joe D
>>> Williams <joedwil at earthlink.net>
>>> *Cc:* John Carlson <yottzumm at gmail.com>; Andreas Plesch <
>>> andreasplesch at gmail.com>
>>> *Subject:* Re: [x3d-public] HAnimDisplacer effect on coord.point
>>>
>>> Here’s what HAnim spec says under Displacer:
>>>
>>> https://www.web3d.org/documents/specifications/19774/V2.0/index.html
>>>
>>> “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*.”
>>>
>>> And here’s what it says under Segment:
>>>
>>> “
>>>
>>> The *coord* field is used for *Segment* objects that have deformable
>>> meshes and shall contain coordinates referenced from the indexed mesh for
>>> the *Segment* object. The coordinates are given the same name as the
>>> *Segment* object, but with a "_coords" appended (e.g.,"skull_coords").”
>>> displacements are an offset from the mesh,  with weight from 0 to 1.  So
>>> weight times displacement is total offset from base mesh.  0 weight = no
>>> offset, 1 weight = full displacements offset
>>>
>>> The Coordinate point is maintained to handle weight = 0.  Weight ranges
>>> from 0 to 1, but double check.
>>>
>>> Joe or Carol might know where to find it in the HAnim spec.
>>>
>>> I believe the answer is, “during rendering,”. Since weight can vary with
>>> animation, and so can displacements, AFAIK.  More than one displacer can be
>>> applied to the mesh.
>>>
>>> I have not read the spec.
>>>
>>> John
>>>
>>>
>>>
>>> On Sat, Feb 8, 2025 at 5:13 AM Andreas Plesch via x3d-public <
>>> x3d-public at web3d.org> wrote:
>>>
>>>
>>> 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
>>> _______________________________________________
>>> x3d-public mailing list
>>> x3d-public at web3d.org
>>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>>
>>>
>>
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