Bugs and issues with post processing materials

Development Rendering
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  • SceneTexture: Specular Color is greyscale
  • SceneTexture: MaterialAO doesn’t work
  • SceneTexture: SubsurfaceColor is greyscale
  • Switch Parameter don’t work (Changing a switch in a MIC has no effect)
  • Missing a SceneTexture: Emissive
  • Seperate Translucency is not in SceneTexture:SeperateTranslucency and instead in SceneTexture: PostProcessing1
  • SceneTexture: PostProcessing2 - 6 are the same as PostProcessing0. What are they intended for?
  • I’m in need of more masks then just the single CustomDepth mask, I created a thread here: Masks - Feedback for Unreal Engine team - Unreal Engine Forums
  • SceneTexture:Lighting and SceneTexture:VertexColors would make a great addition as well that would offer a wide array of post processing uses.
    Currently I calculate lighting by dividing SceneColor with BaseColor but that only works when only using a fully diffuse lit scene: Lighting in post process material - Rendering - Unreal Engine Forums
  • Using TemporalAA with a post processing material that uses more then just PostProcessing0 results in jittering yet TemporalAA is the default setting and it is not explained that FXAA is required.
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HI Davision -

I will try to address your issues though not completely in order but if you have further questions feel free to comment back.

SceneTexture:MaterialAO has been deprecated as a buffer. It was removed to make room for other Shader Models in the engine.

SceneTexture:SpecularColor has also been deprecated and has been since the engine was released but since it was being used in one of our internal projects up until very recently it remained in the engine proper. Since we are using Physically based Rendering Specular Color should be derived directly from Base Color with inputs from Metallic and Roughness.

SceneTexture:SubsurfaceColor is rendering in the correct color as long as you have a subsurface color plugged into the Material’s Subsurface Color input

The Switch Parameter is a known issue, and is currently under investigation.

I am investigating some of the other features you mentioned as well as putting feature requests in for those items you mention above. Once I have further infotmation I will report back here.

Thank You -

Eric Ketchum

Also if you have not, please take a look at the following documentation, it explains a lot of the correct practises with Prost Process materials.

https://docs.unrealengine.com/latest/INT/Engine/Rendering/PostProcessEffects/PostProcessMaterials/index.html

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Thanks! Looking forward to it.
That with SceneTexture:SubsurfaceColor just being greyscale is how it was for me, maybe it is fixed in 4.8 though.
I did all this tests because I’m currently using other SceneTextures like specular and metallic as additional masks and to get other material information to the post processing so I can prototype things while being constrained with the limited passes.

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Just an Update, for reference your feature requests for additional Buffers has been placed as UE-16669.

Regarding the TemporalAA usage, please have a look at the following presentation from Brain Karis regarding the engine’s development of Temporal AA, https://de45xmedrsdbp.cloudfront.net/Resources/files/TemporalAA_small-71938806.pptx

Depending on what you are doing you can move your post process to one side of the Temporal AA Tonemapper and the jitter should be eliminated.