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Large artifacts on mobile

Hey everyone!

I have encountered an issue that I just can’t seem to figure out. I’m working on a mobile game and occasionally will run into large black splotches flashing on the screen. I can’t seem to pinpoint the exact cause, or even figure out when it will occur. I thought it may have been some materials that were not optimized for mobile, but that doesn’t seem to be the case. I thought it may have been a particular asset, however I am seeing this appear in levels without that particular asset, and not appear in other levels with it. It happens very rarely, but it is extremely distracting.

Here is a screenshot taken from an iPad mini2:
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You can see a large black spot on the entire right side of the image. This will flash on and off.
The above screenshot was taken with a cook that had the PVRTC quality set to the lowest, though I see the same artifacts when cooked at the highest.
I also have seen the same artifacts when cooked on an iPad mini retina. They appeared in the same levels, but not always at the same times.

I’m sorry that my description is so vague, I’m just hoping someone else has come across something similar. I have no idea where to begin with solving this.

Thanks! Let me know if you need anymore information.

I think I figured this out. It seems the combination of bloom plus 100% metallic surfaces ended up causing the artifacts. I noticed this mainly on characters, but also some static meshes. I solved it by multiplying my metallic mask textures by .5, or in some levels by simply removing bloom.

Metallic should be either on or off(0 or 1) and not really in between to remain “Physically Correct”. What I would have done instead is adjusted the post process till I got what I wanted.