Computer graphics system and method for capping volume enclosing polyhedron after sectioning

A computer graphics pipeline system configured to cap a polyhedron after the polyhedron has been sectioned against a plurality of sectioning planes defined by a user, the polyhedron having a plurality of polygons, each of the polygons having plurality of edges, the computer graphics system comprises:

• (a) processor means for processing dam, and a memory means for storing said data, wherein said at least one processor operates on each polygon in the polyhedron in a pipelined manner such that each polygon is handled independent of the other polygons in the polyhedron;
• (b) input means for allowing the user to define the plurality of sectioning planes;
• (c) capping means for instructing said processor means how to section and cap the polyhedron in response to the plurality of sectioning planes, wherein each polygon in the polyhedron is sectioned against the plurality of sectioning planes independent of the other polygons in the polyhedron in a pipelined manner, whereby a first polygon in the polyhedron is sectioned against all of the sectioning planes before the processing of a second polygon, wherein said capping means further comprises,
• (1) sectioning means for sectioning each polygon in the polyhedron against the plurality of sectioning planes in a pipelined manner and for generating new polygon edges and intersection points from the plurality of sectioning plane, and for storing said intersection points in one of a plurality of cap edge lists, each of said plurality of cap edge lists for storing said intersection points associated with one of the plurality of sectioning planes, and
• (2) cap formation means for generating for each sectioning plane a cap polygon from said intersection-points stored in an associated cap edge list, wherein said cap formation means includes means for examining said intersection points stored in said associated cap edge list and for matching a selected intersection point that is sufficiently close to said selected intersection point to thereby reconnect the edges of said associated cap edge list to form said cap polygon;
• and
• (d) display means for displaying the polyhedron.

A computer graphics module configured to operate in a computer graphics pipeline system and to manipulate polyhedron formed from a plurality of polygons having a plurality of edges, the computer graphics module comprises:

• (a) a storage medium that can operate on the computer graphics system;
• (b) a polyhedron capping module, connected to said storage medium, that instructs the computer graphics system how to section and cap the polyhedron against a plurality of sectioning planes, wherein the computer graphics system operates on each polygon in the polyhedron in a pipelined manner such that each polygon is handled independent of the other polygons in the polyhedron, and each polygon in the polyhedron is sectioned against the plurality of sectioning planes independent of the other polygons in the polyhedron whereby a first polygon in the polyhedron is sectioned against all of the sectioning planes before the processing of a second polygon, wherein said polyhedron capping module comprises,
• (1) a sectioning module configured to section each polygon in the polyhedron against the plurality of sectioning planes in a pipelined manner and to generate new polygon edges and intersection points from the plurality of sectioning planes, and to store said intersection points in one of a plurality of cap edge lists, each of said plurality of cap edge lists for storing said intersection points associated with one of the plurality of sectioning planes, and
• (2) a cap formation module configured to generate for each sectioning plane a cap polygon from said intersection points stored in an associated cap edge list, wherein said cap formation module includes means for examining said intersection points stored in said associated cap edge list and matching a selected intersection point with another intersection point to determine an intersection point that is sufficiently close to said selected intersection point to thereby reconnect the edges of said associated cap edge list to form said cap polygon.

A computer method of displaying a polyhedron on a computer graphics system as a solid object after the polyhedron has been sectioned about a plurality of sectioning planes defined by the user of the computer graphics system, the polyhedron being formed from a plurality of polygons each having a plurality of edges, the method comprising the steps of:

• (a) section the polyhedron about the plurality of sectioning planes independent of the other polygons in the polyhedron such that each polygon in the polyhedron is operated on in a pipeline manner, whereby a first polygon in the polyhedron is sectioned against all of the sectioning planes before the processing of a second polygon;
• (b) generating new polygon pages and intersection points from the plurality of sectioning planes, and storing said intersection points in one of a plurality of cap edge lists, each of said plurality of cap edge lists for storing said intersection points associated with one of the plurality of sectioning planes;
• (c) examining said intersection points stored in said one of said plurality of cap edge lists in order to match a selected intersection point with another intersection point to determine an intersection point that is sufficiently close to said selected intersection point to thereby reconnect the edges of said one of said plurality of cap edge lists;
• and
• (d) generating a cap polygon for the polygons of the polyhedron that were sectioned against the plurality of sectioning planes, wherein each polygon in the polyhedron is operated on in a pipeline manner.