Patent ID: 7006089

Claim:
A method of generating a representation of an object indicative of the relative visibility of a plurality of polygons of model data of a model representing an image of the object from a viewpoint at which portions of a surface of the object are visible, said method comprising the steps of: receiving model data representing the image of the object and defining the plurality of polygons indicative of at least part of the surface of the object for which visibility data is to be determined; determining for each of the plurality of polygons a visibility value indicative of the ratio of the number of pixels in the image representing visible portions of the polygon from the viewpoint, to a determined greatest number of pixels utilized to represent the polygon from a viewpoint a set distance from the polygon; and generating a representation of the object as viewed from the viewpoint, wherein the visible portions of the surface of the object in the representation defined by the polygons as viewed from the viewpoint are rendered utilizing the respective determined visibility values for the polygons.