Particle lights are not enabled if emitted particles are invisible

I don’t really know if this is a bug or a feature, but for example:

I have particle system which contains two emitters, one for textured quads (it generates about 100 particles at time) let it call “sparks”, second for lights that simulates some combined flicker illumination of “sparks” (it generates 2-3 lights at time).

The problem is, that if I somehow would make second particles generated invisible, setting them initial size or color to 0 or if i would not set this parameters at all, there will be no lights generated by emitter. BUT! I can see spheres if I check “Preview Light Radius” and primitives if I set “Emitter Render Mode” to “Point” or “Cross”. I have spend a couple of days to find out, what was wrong with my light emitter and lights was affect nothing but seems to be generated.

It seems to me, that if particles are not generating, they debug primitives must not be generating to.
And it will be great, if there would be warning in documentation about light particles something like: “If you want to see lights, you must to see particles!”.

Thank you for your attention.
And I’m sorry if my English is not perfect.

Hey Morock,

Can you reproduce this issue in a new blank project in the most recent version of the engine (4.12.4)?

Can you provide me with some screenshot examples of the issue you are reporting?

You are providing me with some explanation as to how to get the issue to occur, but some of the steps are a bit unclear. If you could also provide me with some simple steps to reproduce this issue in a blank project, or if it is easier, supply me with an example project where the issue occurs. That would help me reproduce the issue and enter a bug report.

Let me know if you have further questions or need additional assistance.


Good time ,

Let’s try screenshots.

And if I set Alfa color to some not zero value, every thing will OK.

The issue is that I can see that light spheres in particle system editor and that’s why I expect to see lighting in scene. It’s misleading.

This is technically not a bug because the lights are still being told to spawn, but they just do not have a color/alpha being shown. The light radius is still being rendered because there is a light spawning.

There would be a bug here if you set the alpha to 0 and it still rendered as default, or if he spawn rate was set to 0 and the lights still spawned.

Let me know if you have further questions or need additional assistance.


Technically, yes it is. But it is misleading.
Is documentation describes that behavior somehow?
I’d like to read about small things like this, because it’s make me sad to find out them by myself.

Thank you!

Thanks for the report. At this time we are only addressing major bugs in Cascade, while we plan for the particle system’s future replacement. Issues like this will hopefully not exist within the new particle editor, but if it persists please let us know and we can continue with the bug reporting process.

Thank you,