color assign?

hello,

i'm trying to figure out how to assign rhino material colors to objects using the shader interface in grasshopper. Its nice to view the gradient as a grasshopper preview, but I want to render with the colors. Ideally, I want to assign colors through lists (each object will have a different color, according to a preset gradient).

I've looked around and found a few threads about this, but havent had any luck actually making it work. Does anyone have a definitive process to assign a Rhino Material color through grasshopper - sort of like "baking" the objects' material properties?

thanks.