C4D, Thea and a few others have frontal projection uv mapping, this feature is awesome for mapping a floor plane to a HDRI.

An example would be this:



the only geometry in the scene is the car and the floor plane its stood on, the rendered background image is projected onto the ground.. obviously it'll only work with static scenes, there is also Camera projection which projects what the camera see's onto the ground

yeah, this is a interesting technique, looks good for static scene.