Here is a quick demo using the blend function and the additional lut function. Starting with a night grade LUT and randomly flashing to a lightning grade LUT, effectively blending between them smoothly. The LUT shader is applied to a layer above everything and manipulated using the layer object.
LUT Demo <- Download
MuddyMole, this is perfect. Absolutely perfect with all the needed functions.
I use 3D LUTs to emulate film-stocks and do cinematic color grading. Some of my work on video games can be seen here:
For Fallout 4
Vintage Film Looks - Emulating older film-stocks from the early-mid 1900s
Modern Film Looks - Emulating modern film-stocks
Cinematic Film Looks - Emulating advanced cinematic color grading from movies and my own creations