Patent US 5,870,099

A method, apparatus and computer program for generating a perspective projection of a three-dimensional object compatible with a two-dimensional perspective background image. In the invention rectangular parallelepiped guide figure is displayed on a two-dimensional background image. According to inputs from a user, a rectangular parallelepiped guide figure manipulation routine deforms and moves the rectangular parallelepiped guide figure. Once the rectangular parallelepiped has been manipulated to correspond to key features of the background image, a camera angle calculation routine calculates the camera angle, such as the eye position, the viewing direction and the field of view angle for the rectangular parallelepiped guide figure. Using the calculated camera angle, a perspective drawing of a three-dimensional object compatible with the two-dimensional perspective background image is generated.