O.K, let's take this one step further and say that the painting was published in a "Making of book" or something similar.Still legal?

Yes,O.K, I phrased incorrectly. I want to use a warehouse model(that someone else made). Export a specific angle in 2D. Do a full blown photoshop painting over it. Present it to the director.Is this legal?

Is SU royaty free? Can I use models for reference, that other folks made, at my company?