how to generate 3d lut by many RGB Color pairs?

[1623275623]

I have so many color pairs which is source color and target color. I want use these pairs to generate a 3d lut file? How I can do it? I want to konw whether OCIO will generate lut i need. thank you.

[KevinJW]

Unfortunately OCIO doesn't really have any tools to generate a LUT file from a set of colour pairs.

However, in terms of making a LUT that OCIO can read, there are a number of formats which are simple text files, if your measurements are in the form of uniformly spaced sampling of the 3D cube, you might find it easy to format your measurements in a format like this https://github.com/AcademySoftwareFoundation/OpenColorIO/blob/main/src/OpenColorIO/fileformats/FileFormatSpi3D.cpp#L19 You would need to adjust the line containing '32 32 32' to match the number of readings you have., but everything else in the header should probably remain the same.

If you have non-uniformly sampled, or some other distribution of data then you would need something that deals with sparse data and I'm not sure we have something for that.