>>If I make a cube in MoI and import it into Carrara, I apply a shader to the cube.
>>It doesnt allow me to apply a different shader or material to six different sides.

Hi Burr,

As Brian mentioned, you can make planer mapping for a cube. You also have the option of creating shader domains, which could also be used for a cube,but, shader domains can be used for any object with any number of sides and each side (or face) can be given a different color.