Any good workflow for LUT texture authoring?

bitinn · Jan 2021

Hi,

I am recently experimenting with tone mapping in game and one thing I don't quite enjoy is to open photoshop and manually create cube files.

Unfortunately my engine and pipeline (Unity + HDRP) only accepts cube files, not HALD strip texture (1024x32), so I need to think of a workflow that allow me to both tonemap and export to cube files.

I wonder if there are ways we can do this in other smaller tools (be it premium, open-sourced, or web-based), or things like Substance Designer, which we can quickly iterate the result.

Suggestion welcomed!

sprunghunt · Jan 2021

You could easily make something in substance designer that converts a cylinder to a cross shaped cubemap.

I would have used cubeMapGen before that:
https://gpuopen.com/archived/cubemapgen/

poopipe · Jan 2021

It's not a cubemap, it's most likely stored as a 3d texture

Based on a brief read of the documentation it looks like Photoshop is probably the easiest way to do the job tbh.

The issue is not creating the correct data (although that's a challenge on itself) it's exporting the correct format.
You could make an exporter for substance designer if you put the work in but it would be a distinctly non-trivial exercise.

You might find something useful if you start digging here though
https://opencolorio.org/

bitinn · Jan 2021

Thx, I end up using these 2 tools:

Affinity's LUT export feature:

https://affinity.help/photo/en-US.lproj/index.html?page=pages/Adjustments/export_3dLut.html?title=Exporting custom adjustments as LUTs

And Polarr, a web-based tool that can do a bit quick LUT adjustment:

https://wiki.polarr.co/wiki/product-features/3D-LUT.html

Eric Chadwick · Jan 2021

I used to use Photoshop for this, when I was working with a custom engine that used DDS cubes. I'd screenshot the game, use adjustment layers on it, import the LUT (nvidia's dds plugin would lay out the cube levels and mips), then drag the adjustment layers into the flattened cube, flatten, re-export to DDS.

Any good workflow for LUT texture authoring?

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