Konstantin Magnus posts a look at modeling from photographs in Cinema 4D. More than just using photos for reference, Konstantin shows how you can slice up the photo with polygons that will create a 3D shape out of it. The photo then becomes the texture for the model.
Photo modeling offers a fast and fairly accurate way to extract 3D information from a model. As the photo ends up being the texture for the model, it also gives you a quick way to get something fairly realistic.