Rear projection (RP) in Virtual Production

Rear projection (RP) is a Volume Operations term in filmmaking. In virtual production, the nuances of this term take on special meaning. Here, we break down the definition to give you a starting point.

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Basic Definition:

What is Rear projection (RP) in virtual production?

Rear projection is an in-camera compositing technique used for decades to create the illusion of depth and realism. By displaying a pre-photographed background plate or 3D environment behind the foreground subject, directors have been able to easily achieve shots of cars driving through realistic environments or actors interacting with images projected onto screens. This same process is still being used in virtual production setups, but it goes by another name: green screen lighting. 

When making rear projections in virtual production, there are several things to consider. First, you must ensure that your projector's brightness is set appropriately. Too much light will wash out the green screen, while too little can cause problems with casting shadows on the background image. Additionally, camera movements must be considered when setting up lights, as they can also affect how well the background is seen. Finally, make sure your green screen material itself is evenly lit throughout – if one area is darker than the rest, this can create problems for keying later on in post.

Rear projection has been featured in some of the most iconic film sequences of all time. For example, Alfred Hitchcock’s Vertigo (1958) features a car driving shot through San Francisco using rear projection technology – something that was revolutionary at the time. In modern cinema, The Wolf Of Wall Street (2013) famously uses rear projection during its “Lemmon 714” sequence. Rear projection is still very much alive and kicking in virtual productions today, albeit with different names and technologies.