I do it both ways on occasion, depending on the scene. I use the Bryce bmp on either a square prop, or nerds backdrop (runtime dna's infinity cove would be the same, and free). If this doen's work I export the characters as obj and then put them into the scene in bryce.

The greatest part of wisdom is learning to develop  the ineffable genius of extracting the "neither here nor there" out of any situation...."