An Automated Approach to Feature-Based Design for Reusable Parameter-Rich Surface Models

Abstract

Clamshell casting is a popular manufacturing technique where liquid is poured into a mold or cast and the cast is removed once the liquid has hardened. The term clamshell refers to the way in which the cast is removed. The two cast parts are removed by rotation through a hinge much like a clamshell. Given an object, modeled by a polyhedron P of arbitrary genus with combinatorial complexity n , we determine when the surface of the polyhedron can be decomposed into two parts s.t. each part can be rotated around a line in space without colliding with each other or intersecting the interior. Such a line is a valid casting line. Specifically, we solve the following problems: (1) Given a line l in space, we determine in ( )O n time whether l is a valid casting line for P . If degeneracies are present, such as a reflex edge or face of P is perpendicular to l , the running time increases slightly to ( log ) O n n . (2) In 4 ( ( )) α O n n time, where ( ) α n is the inverse Ackermann function, we report all combinatorially distinct valid casting lines. The running time is 4 ( log ) O n n in the presence of degeneracies. All of the running times are shown to be almost optimal.

A Computer Aided Design Modeler for Designing the Plastic Components Using a Set of Programmatic Operations

“…of features and thousands of parameters and so more advanced methods have been developed that modify geometry at an even higher level [12,10]. A graphical user interface (GUI) supports the whole feature class definition process.…”

CAD-Centric Dynamic Workflow Generation

“…Examples of the dimension values for a rigid model are displayed in Table 2-2. The use of parameters as dimensions is referred to as parametrics and is vital to creating flexible CAD models, and opens the doors for fast design iterations and part optimization (Elliot 2007). …”