[x3d-public] Proposal for New Fields for ParticleSystem

[Holger Seelig]

John,

Random scale can not be done with my approach, but complicated formulas like (r = A + B * cos(C * phi) * cos(D * theta)), if you sample some keyframes. To have some randomness you can and should write your own shader (I know this seems not an option for you).

Best regards,
Holger

—
Holger Seelig
holger.seelig at yahoo.de


> Am 29.10.2025 um 22:39 schrieb John Carlson <yottzumm at gmail.com>:
> 
> Holger, this appears to be nearly what I wanted in my VariationalPhysicsModel, except I made my scale based on random variations within a range.   This was so I could animate the equation:
> 
> r = A + B * cos(C * phi) * cos(D * theta)
> 
> A, B, C and D are all scaled independently according to random values, with limits.
> 
> If you could show a demo (does the one below have it?) with randomized scale over time, great!
> 
> On Wed, Oct 29, 2025 at 12:42 PM Holger Seelig via x3d-public <x3d-public at web3d.org <mailto:x3d-public at web3d.org>> wrote:
>> The new latest of X_ITE comes now with two new fields for ParticleSystem. That are scaleKey and scale fields. They work much like colorKey and color fields.
>> 
>> A user asks me for the ability to scale the particles during the time, basically to make the particles grow from its creation time and then shrink.
>> 
>> Other 3D engines like Unity have this already for a long time.
>> 
>> With the two new fields it is possible to have a curve and finely adjust the size over the time.
>> 
>> New fields will look like this:
>> 
>> inputOutput MFFloat scaleKey [ ]
>> inputOutput SFNode scale NULL  [Coordinate]
>> 
>> It will work with all geometry types a ParticleSystem can have, even GEOMETRY.
>> 
>> I prepared a very simple example that shows the capabilities of these new fields:
>> https://create3000.github.io/x_ite/playground/?url=https://create3000.github.io/Library/Tests/Components/ParticleSystems/Scales.x3d
>> 
>> Best regards,
>> Holger
>> 
>> —
>> Holger Seelig
>> holger.seelig at yahoo.de <mailto:holger.seelig at yahoo.de>
>> 
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