Particle System Entity Fixes


Hey everyone,

Beta release 70 will contain some fixes to Particle System Entities. There are no real new features, but many of the properties of particle systems were so broken that the fixes could result in visual changes. The changes are as follows:

  • the alphaSpread, radiusSpread, and colorSpread properties now work. This means that if you had them set as anything other than 0, your particle systems were rendering incorrectly, but will now appear as intended.
  • the speedSpread property now works on point emitters
  • the start/finish properties now work. Under certain circumstances, the colorStart, colorFinish, alphaStart, alphaFinish, radiusStart, and radiusFinish properties wouldn’t work properly or would appear different to other users. The intended behavior was that if these properties weren’t set, they would be equal to the corresponding middle value (color, alpha, particleRadius).

Basically, all properties should be used correctly now. We apologize if this affects your content in any way. Let us know if you have any questions!


Have they fixed the import/export errors, one big problem was exporting particles via json file completely broke it, this resulted is the inability to properly transfer or set to marketplace any particles.
Especially the “will follow” parameter did not export.

(glad to see the particles finally getting some love)


Import/export should be fixed! I believe the start/finish properties wouldn’t transfer correctly, as well as the emitterShouldTrail property. Let me know if you find any remaining issues!


Thanks for this work. I can uncomment some of my controls :slight_smile:
If you ever have a wishlist for new features. adding a rotation and rotation velocity setting would be cool.
also a flip setting and flip velocity


Yep, rotation is on my todo list. What’s flip?


Flip would be making the texture thiner in one axis untill its a line and then inverting it so its backwards as it gets thicker again,. Gives the illusion that a 2d texture is rotating in Z axis (3d).

Another feature would be to make the textures setting an array with multiple textures that can either be cycled in order or radnomly.


Would be nice to be able to support dark particles. For example, we can’t do dark smoke.


Sure! I’ll take note of these.


This is a little more difficult. Our particles use additive blending (which is why black is invisible). Doing proper blending requires sorting all the particles to render them in the right order, which is expensive. But we’re aware that this is desirable, and we’ll work on it.


Another thing while your working on rotation. Currently the particles rotate with your head, so like my lightning particle effect looks good in desktop mode. But in VR mode, when you turn your head sideways, the particles follow. so the lighning is going sideways as well.


I am a noob and am researching the particle capabilities of HiFi and wondered if it was possible to create an avatar that is made only from particles that follow an invisible body?


When you’re done with the particle fixes you might also take a look at the spotlight code
and add cookies w/ rotation support so we can have different shaped spotlights,


Spotlight s with image projectors for both still images and video


Also a strobe mode for both particles and spotlights.
With Frequency, duty cycle. or ranom modes.


Spotlight improvements are also on our todo list :slight_smile:


I think you could approximate this pretty well by creating an invisible avatar and parenting particle entities to a few joints on yourself. You can play around with the radius and the emit directions and enable “Emitter should trail.” Other folks on here might have better suggestions!