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Hidden Line Elimination for Two Dimensional Display of Three Dimensional Objects

IP.com Disclosure Number: IPCOM000080489D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Schreiber, DE: AUTHOR

Abstract

A hidden line elimination program determines the location and aspect of every line segment of surfaces of three-dimensional objects and scenes, based upon the viewing angle and eye position. Those line segments that are on the reverse side of the object or are hidden from view by other surfaces, are eliminated from the display.

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Hidden Line Elimination for Two Dimensional Display of Three Dimensional Objects

A hidden line elimination program determines the location and aspect of every line segment of surfaces of three-dimensional objects and scenes, based upon the viewing angle and eye position. Those line segments that are on the reverse side of the object or are hidden from view by other surfaces, are eliminated from the display.

The calculations to determine whether line segments are hidden are based upon a definition of each line segment as the base of a triangular plane, the apex of which is the viewing position of the eye.

In the instant system, line segment storage is structured to store only the eye-to-line plane definition equations for the "contour line" segments of a scene. The contour line segments are those which represent an outline of the object surfaces from the viewing point. All other stored segments are represented as lines and are stored separately. Thus, a sequencing algorithm may be used for processing the contour line segment data, without searching for contour line segments from the totality of line segments.

The processing of the data is conducted on the basis of sequential processing of adjoining faces of the surface of each object, to determine whether line segments or portions thereof are hidden. This allows skipping the recalculation of line segments and apexes that have already been calculated and processed.

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