As front projection and bluescreen effects became more widespread and less costly, rear projection has been rendered largely obsolete. Quentin Tarantino used the process for the taxi ride sequence of "Pulp Fiction", and James Cameron used rear projection for several special effects shots within "Aliens", including the crash of the dropship as well as for several important sequences in "" such as the car escape from the mental hospital and the T-1000 hijacking the Police helicopter; he has been described as one of the few people in Hollywood still able to understand and use process photography as an effective technique. Also, the Austin Powers film series frequently used rear projection to help give it the feel of old spy movies; "Natural Born Killers" used the technique extensively throughout to emphasize characters' subconscious motivations.