Method and system for determining visible parts of transparent and nontransparent surfaces of three-dimensional objects

A system for determining the visibility of surfaces of three-dimensional objects, projected on a view plane from data defining said surfaces of three- dimensional objects, said system comprising:

• a) a central processor programmed to
• a) derive data indicative of boundaries of projections of said surfaces on said view plane,
• b) determine a finite number of subdivisions of said view plane thereby providing perimeters of each of said subdivisions,
• c) determine points of intersection of said perimeter of one of said subdivisions with said boundaries of said surfaces projected on said view plane;
• d) determine the distribution of surfaces visible along said perimeter of said of one of said subdivisions by utilizing said points of intersection, and
• e) determine if said one subdivision is terminal from at least said distribution of surfaces visible along said perimeter of said one subdivision.

A computer-readable medium having computer-executable instructions for performing a method comprising:

• a) deriving data indicative of boundaries of projections of said surfaces on said view plane,
• b) determining a finite number of subdivisions of said view plane thereby providing perimeters of each of said subdivisions,
• c) determining points of intersection of said perimeter of one of said subdivisions with said boundaries of said surfaces projected on said view plane;
• d) determining the distribution of surfaces visible along said perimeter of said of one of said subdivisions by utilizing said points of intersection, and
• e) determining if said one subdivision is terminal from at least said distribution of surfaces visible along said perimeter of said one subdivision.

A method of determining visible parts of transparent and nontransparent surfaces of three-dimensional objects, said parts visible from the side of the view plane established according to desired orientation of the objects, the method including the following steps:

• providing input data defining the surfaces of three-dimensional objects the visible parts of which are going to be determined,
• converting said input data in order to obtain boundaries of projections of the surfaces on the a view plane,
• dividing the view plane into the finite number of subdivisions by means of division lines, said resulting subdivisions are bounded by contours comprised of segments of division lines,
• determining the points of intersection of the division lines with said boundaries of projections of surfaces,
• determining distribution of visible surfaces along the contours by utilizing said points,
• setting the predefined condition, with fulfillment of which for subdivisions visible parts of those surfaces, which have projections located at least partially inside these subdivisions can be determined, and setting the means, for said condition, for determining visible parts of that surfaces inside these subdivisions according to distribution of visible surfaces along the contour of subdivision,
• determining the terminal subdivisions, i.e. the subdivisions for which the said condition is fulfilled and determining by said means the visible parts of surfaces, among those parts, which have projections located at least partially inside the terminal subdivisions.