I am not absolutely sure as far as it has turned out beautifully after post-processing, but the basic idea consisted in literal understanding "to get wasted in modeling". After modeling some things have remained undecided nevertheless which, I think, I will solve shortly. Besides modeling I only understood how to work with primitive light sources and standard settings of defuse mesh color. I didn't understand how to work with passes and save them for multi-pass in MODO. Existence of them would help me to solve several problems with texturing and over-peinting at once. I have decided don't stop on a standard default mesh in the greyscale and have made a little unrealistic over-paint in WH40K Universe style.