Ok, what am I missing here, why not just use step effector + multishader in color mode instead of index ratio?
Apart from the fact that you are going to be using C4D Bitmap instead of ImageTexture nodes it seems to work just fine. I'm not sure but I think I even saw a script somewhere that can convert C4D Bitmaps into ImageTexture nodes.
Edit: Here is the script, thanks to pxlntwrk for the link:
https://render.otoy.com/forum/viewtopic.php?p=290502#p290502Either way dealing with 100s of textures that are read from disk is a messy way of doing this no matter how you are rendering it. I prefer to use a sprite-sheet and offset UVs using OSL. That way instead of dealing with hundreds of maps I'm only dealing with one and it's lightning fast because all of the maps are preloaded in VRAM together in a single texture map and it's super easy to deal with alpha channels or exr layers ( only in Standalone for now because layers are not yet integrated in the C4D plugin
)
With regards to the Gradient node, IIRC it can handle up to 256 textures and there is a
lua script that can automatically load textures from a folder and connect everything. You can save your material into LocalDB and bring it into C4D.
Cheers
Milan