I'd rather just edit the standard materials that unity does bring in, because they are all already assigned to the objects that i import, rather than having to re-create each and every materials and reassign to each object or is that not a good plan? i sure don't want to change every material in my 3ds max scene and then export - as i need to keep that as is. Now, when i export from 3ds max, i get an error that some materials are not compatible (ie, the IRAY+ material is not compatible with FBX and i know this) but still, it exports as a standard material (which is supported by Unity) yet, i can't edit it in anyway as everything is greyed out.

there is no option to simply change the color or add the bitmap. i see the material, i see shader = standard, but then everything is greyed out. When i import this into unity, i can't edit or change the 'bark' material or the 'leaves' material. the bark and leaves are each IRAY+ materials that have diffuse bitmaps.

I've exported a tree from 3ds max, the material in 3ds max is a standard multi/sub-object material, the two materials are bark and leaves.

3ds max material editor