Proper Texturing Workflow for Unreal Engine

[daskyler (Skyler Dawson)]

Thank you all so much for your quick responses. Couple follow-ups:

@Thomas_Mansencal

@daskyler

When should we (or do you) adjust the tonemapping curve to ensure our textures are supporting the result we want?

Never! By adopting a fixed View/Display Rendering Transfom (DRT), you ensure that all your assets are authored in a consistent way which makes them easy to share across shows/games. The other side of the coin is that if they are authored while respecting PBR common sense, they should look good no matter the DRT.

To make sure I’m interpreting this correctly: you’re advocating avoiding touching any of the filmic curve parameters UE exposes like slope/toe/shoulder, since that is meant to be a fixed standard, and any adjustments to be done through LMTs (UE’s color grading categories)?
To go back to what spurred this topic, the original rock texture done in Substance, using their default linear tonemapper, had a lot of colour detail that ended up disappearing after tonemapping. Am I correct that this likely means our albedo was authored with too bright colours? And we should author based on no changes to the color grading categories & the default ACES curve.

@Thomas_Mansencal

ACES 1.1 will not change anything and we are at 1.2 btw The easiest way, for now, is to use the following OCIO colourspaces and disable the Gamut Expansion and Blue Light Artifact Fix as indicated in the UDN Question:

I read the UDN link - to disable these changes, you locally modified the PostProcessCombineLUT shader, correct?

@Dogway

Hello, my disagreement with @Thomas_Mansencal was ONLY about having the option for “Output - sRGB” as IDT (talk about nitpicking). But as I said it’s an option not an enforcement, you can also choose “Utility - sRGB - Texture” as IDT to conform to standard ACES.

Thank you for clarifying Jose; I must admit that at first that discussion had gone over my head, so the exact disagreement was unclear.

@Dogway

Using the contained LUTs that do sRGB —> ACES2065-1 —> RRT —> ODT is a landmine field, colors don’t go well through the log shaper for Substance Painter LUTs. My version doesn’t do any color work, it’s only the tonemapping part.

What is the ‘log shaper’? Which part of the transform does it affect?

@bleleux

The gamut expansion is subtle enough to ignore for the average texture in my experience unless you’re working with saturated colors near the Rec.709 boundary. The blue light fix may be more of a common issue since it has a bit of an effect into cyan and purple, but the blend is arbitrary and may not even be necessary. I generally disable it unless I need it- it’ll be pretty obvious if you have any bright blue emissives and don’t use the correction.

Good to know. I’m going to see what effect it has on our current content if we revert back to standard ACES, but depending on our VFX going forward I may need to bring back the blue light fix as you point out.