Particles from multiple particle emitters not rendering correctly when overlapping

Reproduction Steps
When multiple different particle emitters are in close proximity to each other the game engine will always render the particles generated from the emitter closer to the camera over the ones generated by the other emitter regardless of the actual 3D position of the particles.

EDIT: I should also add that this bug predates the release of particle flipbooks

Expected Behavior
The generated particles should be rendered on top of each other based on their actual position relative to the camera regardless of which emitter they originated from.

Actual Behavior
Particles of different particle emitters are rendered on top of each other purely based on the position of the emitter as seen here:

An example for this can be found here:

Issue Area: Engine
Issue Type: Display
Impact: High
Frequency: Constantly


Is there any Transparency in the Particles? If so then rendering has always been an issue for transparent parts/decals/etc. that are in front of other transparent Parts.

If not then it’s probably similar to the issue of z-fighting in ovelapping Parts. The rendering engine can’t decide which surface to display since they are both the identical distance from the camera.

Nothing to do with the transparency level, the issue occurs even with fully opaque images.

Z-Fighting is something else and unrelated to this as the engine has a clear priority which particles it should render on top.
The problem is that it prioritizes the position of the emitter over the position of the actual particles when deciding which particles should be rendered on top which is why you can see them flicker in the video as I change the position of my camera and as it changes which emitter is closer to it.

I might be totally wrong but this behavior has been around for quite a while and looks like it functions as it would’ve normally.

Is there a post where it is intended that the behavior work as the actual behavior you described? I don’t remember seeing a post describing the behavior you said though that probably just means I don’t look around too much :sweat_smile:

Thanks for the report. This is the intended behavior since there’s no ZIndex/layering property you can edit for particles.

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