I was gathering some information on the glorious Ray Casting technique. As far as I've understood it's not a complete 3D rendering, and that's why objects and NPC's are often displayed as simple sprites (I might be wrong here, of course).
Then I've stumbled upon the Dark Forces' engine by Lucas Arts, called Jedi Game Engine and back in the days they were able to include fully 3D objects. Then a question arises: how did they do it? Do the objects "simply" boil down to a complex mixture of walls and floors?