I just tried to make a water shader using translucent material. I set it up this way:
Screen Space Reflections [v]
Lighting Mode [Surface TranslucencyVolume]
Directional Lighting Intensity [1.0]
Use Translucency Vertex Fog [v]
And some other settings.
it all worked fine.
Than I enabled tessellation.
Boom!
My material suddenly turned into some sort of emissive flickering magic ball. Horribly looking one. Well… I started to play with the settings and once I disabled Use Translucency Vertex Fog, it fixed itself.
It appears that the fog + translucency + tessellation = magic emissive something.
What you’re seeing is likely related to using Shader Model 5 (Unreal Engine Issues and Bug Tracker (UE-32865) ). If you open the project without the -openGL4 specifier or go to Settings->Preview Render Level->Shader Model 4 this issue should be fixed. If you are still seeing the flickering, please post a screenshot of your material setup and details.
Yes, it is specific to SM5. However, this can’t be any way possible in SM4 because there is no tessellation in SM4. This only occurs with tesselation enabled on translucent materials with fog enabled. A very case-specific glitch that’s only possible in SM5. I just pointed this as a fixme. However, it seems that the bug is already reported - great to hear!
I found out another workaround using Shader Model 5.
You can change your Shading Model to “Two Sided Foliage” on your Translucent material. If you do that the weird flickering from lights (specifically spotlights for me) that appear only with Fog + Light behind a translucent material.
