Resolved Strange particles randomly appear for a short period of time

Hi,

I am not exactly sure whether this is a bug, it might just be some parameter that I haven't adjust correctly.

This is something I made with VFX graph and using URP, all in 2D. The light globe near the center of the image is the problem: it appears just for a very short period and then it vanishes. However this kind of globe appears quite often and I am pretty sure none of my particles resemble this globe. The globe can also have different sizes which make this even more mysterious.

Nothing is wrong when I preview the VFX in the inspector or out of Play mode.

I also made some textures with shader graph, and applied it to line renderers. And in this case the globes can also appear.

Using: Unity 2022.2.0a10, URP 14.0.2, Shader Graph 14.0.2, VFX Graph 14.0.2



Also using Post Processing volumes that comes with URP, if this helps.

Output Particle Quads are typically like this:

 

Asumming you mean big purple dot near middle, isn't that result of bloom?
Try turning off the bloom and see if this still happens.

In case it's fault of bloom it happens probably because there are two particles in the same position (or other elements) and with additive blend mode they "stack" the intensity and in result you get super intense bloom in this place. You can fix it by making them not additive or adjusting bloom settings to make it less intense.

 

Thanks, it does seem to be the problem of the bloom... When I deactivate the bloom the effect no longer appears. However, changing output quad to non additive (I changed it to alpha) does not solve the problem...

 

Hard to tell from single image, but I guess those blue/purple lines are also additive and maybe rendered on top.
Or possibly

Set Color Over Lifetime

has some alpha/intensity jumps. When you know it's bloom, then you need to find what causes huge intensity in that place.
btw there is option to clamp huge intensity in PP

 

I tried to reproduce the issue in a clean project but I failed... But finally I located the problem. It is actually in a shader graph that I didn't clamp a value before passing it to the power node. With clamp added it no longer produce this problem. It was also my mistake to state that it had something to do with the VFX graph...actually those vfx are used at the same time as the problematic shader.