<html aria-label="message body"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">John,<div><br></div><div>Random scale can not be done with my approach, but complicated formulas like (<font color="#000000">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).</font></div><div><font color="#000000"><br></font></div><div><font color="#000000">Best regards,</font></div><div><font color="#000000">Holger</font></div><div><br id="lineBreakAtBeginningOfMessage"><div>
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<div><br><blockquote type="cite"><div>Am 29.10.2025 um 22:39 schrieb John Carlson <yottzumm@gmail.com>:</div><br class="Apple-interchange-newline"><div><div dir="auto">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:</div><div dir="auto"><br></div><div dir="auto">r = A + B * cos(C * phi) * cos(D * theta)</div><div dir="auto"><br></div><div dir="auto">A, B, C and D are all scaled independently according to random values, with limits.</div><div dir="auto"><br></div><div dir="auto">If you could show a demo (does the one below have it?) with randomized scale over time, great!</div><div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Wed, Oct 29, 2025 at 12:42 PM Holger Seelig via x3d-public <<a href="mailto:x3d-public@web3d.org">x3d-public@web3d.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="line-break:after-white-space">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.<div><br></div><div><font>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.</font><br><div><br></div><div>Other 3D engines like Unity have this already for a long time.</div><div><br></div><div>With the two new fields it is possible to have a curve and finely adjust the size over the time.</div><div><br></div><div>New fields will look like this:</div><div><br></div><div>inputOutput MFFloat scaleKey [ ]</div><div>inputOutput SFNode scale NULL [Coordinate]</div><div><br></div><div>It will work with all geometry types a ParticleSystem can have, even GEOMETRY.</div><div><br></div><div><div style=""><font><span>I prepared a very simple example that shows the capabilities of these new fields:</span></font></div><div style=""><a href="https://create3000.github.io/x_ite/playground/?url=https://create3000.github.io/Library/Tests/Components/ParticleSystems/Scales.x3d" target="_blank">https://create3000.github.io/x_ite/playground/?url=https://create3000.github.io/Library/Tests/Components/ParticleSystems/Scales.x3d</a><font></font></div><br></div><div>Best regards,</div><div>Holger</div><div><br></div></div><div>
<div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div dir="auto" style="text-align:start;text-indent:0px;line-break:after-white-space"><div style="letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">—</div><div style="letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;">Holger Seelig<br><a href="mailto:holger.seelig@yahoo.de" target="_blank">holger.seelig@yahoo.de</a><br><br></div></div></div></div></div></div></div></div></div></div></div></div>
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