Filmmaker Fred Olen Ray has been very generous in letting me share these with you two pics of a scene, shot using the forced perspective method, from his latest film, Nuclear Hurricane.
The first pic below shows a shot which utilized forced perspective and a foreground model placed inside a matte box which has miniatures built inside of it. Think of it as a miniature studio set which is being combined in camera with the background.
The reactor in the middle is a salad bowl that Fred Olen Ray picked up from a Walmart. Actor Jack Scala stands a distance away in front of the the camera as part of the background to achieve the ultimate illusion that he is standing inside a nuclear reactor room.