[x3d-public] Proposal for New Fields for ParticleSystem

[John Carlson]

I would prefer if the pseudorandom list of scaleKey values to be created as
a particle system, similar to how WindPhysicsModel works, rather than
explicitly creating such values.  Indeed, when I tried to create
VariationalPhysicsModel, I used WindPhysicsModel as a basis.

I don’t want to “swap out” Coordinate nodes, I want 6 separate
VariationalPhysicsModels, or 6 scaleKey fields that are like particle
systems.

I realize I can use a script, but I really want to do this integrated with
the GPU, because JavaScript computation of surface coordinates on the
surface is way too slow.  The 6 scale keys are key to generating the
surface.   If I have any hope of scaling this up to thousands of surfaces,
it’s got to be on the GPU.    That is, I’ve got to have any randomness
ultimately on the GPU, or pseudorandom numbers streamed to the GPU.

A whole another aspect is having the 6 scaleKey current values controlled
by multiple users, but that’s a whole another project.

John

On Sun, Nov 2, 2025 at 7:45 PM Don Brutzman via x3d-public <
x3d-public at web3d.org> wrote:

> John, it is straightforward to generate a pseudorandom list of scale
> values using the *scale/scaleKey* field definitions that Holger has
> recommended.
>
>    - Create a Coordinate node that has a list of individual SFVec3f scale
>    values in the MFVec3f Coordinate.points field.  As Holger indicated, you
>    can sample that using however many *scaleKey *intervals you want.
>    - If one jittery Coordinate node isn't enough for you, you can
>    generate more than one and swap them out.
>    - Generation of such pseudorandom Coordinate nodes can be done
>    programmatically at authoring time.
>    - Generation of such pseudorandom Coordinate nodes can also be done at
>    run time using a Script node.
>
> Hopefully the draft specification prose helps untangle this.  The 3-tuple
> scale values go into the Coordinate node points field, and a scaleKey array
> lists corresponding time in seconds for each transition.
>
> There is a lot of expressive power here.  Have fun with X3D ParticleSet
> particle scaling!   😀
>
> all the best, Don
> --
> X3D Graphics, Maritime Robotics, Distributed Simulation
> Relative Motion Consulting  https://RelativeMotion.info
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