GEOMETRIC ASSISTANCE FOR THE CONSTRUCTION OF NON-POLYHEDRAL SOLIDS FROM ORTHOGRAPHIC VIEWS

摘要

As the extensive use of solid models becomes widespread,it is important to have a mechanism by which existingengineering drawings can be converted into solid models.Therefore, a geometric assistant which can aid in theconstruction of solid models is beneficial. In this paper, wepresent key operations for a system called the Assistant for theRapid Construction of Solids (ARCS), that provides thisassistance given a set of two orthographic views. ARCS isbased on the Visual Reasoning Tutor (VRT), a system wedeveloped that provides users with the geometric framework tobuild polyhedral solids from their orthographic views.However, the geometric domain of ARCS encompasses nonpolyhedralsolids with cylindrical and spherical surfaces, suchas those found in typical mechanical parts. We have devised theCylindrical and Spherical Warping operations to createcylindrical and spherical surfaces, which use interactivecomputer graphics that guide a human user to build nonpolyhedralfaces of a solid. These operations are then illustratedwith an example using ARCS to create the solid model of atypical mechanical part from its orthographic projections.