Patent ID: 7388583

Claim:
A method of scaling a three-dimensional input model ( 200 - 208 ) into a scaled three-dimensional output model ( 210 - 224 ), the method comprising: determining for portions of the three-dimensional input model ( 200 - 208 ) respective probabilities that the corresponding portions of the scaled three-dimensional output model ( 210 - 224 ) are visible in a two-dimensional view of the scaled three-dimensional output model, the determining (a) being based on a projection of multiple projections of the three-dimensional input model ( 200 - 208 ) in a viewing direction and (b) being based on a viewing angle and depth-range capability of a display device, further wherein determining respective probabilities that the corresponding portions are visible includes assigning to elements stored in a z-buffer stack a designation of (i) type I for a portion that definitely will be visible in one of the projections, (ii) type II for a portion that most probably will be visible in one of the projections, (iii) type III for a portion that most probably will not be visible in one of the projections, and (iv) type IV for a portion that definitely will not be visible in one of the projections; and geometrically transforming portions of the three-dimensional input model into the respective portions of the scaled three-dimensional output model on basis of the respective probabilities, wherein geometrically transforming of the portions comprise one of clipping, translation, rotation, or deformation, wherein no depth-range of the display device is wasted in the scaling for eventually invisible portions of the scaled three-dimensional output model.