Feature-based geometric modeling using B-spline surfaces and a natural language approach

Traditionally, design geometries are represented using orthographic views which require a human being to interpret them and recognize geometric features to evaluate the design. Solid modeling systems have made the task somewhat easier, but they often require tedious and complex operations using simple geometric primitives. This has led to investigation of modeling systems which allow the creation of assemblies the way engineers conceive them - as features. To be able to efficiently describe models in terms of features, a rich set of feature descriptors are necessary. An exhaustive study of English words describing form, shape, feature, shape altering transformations and surface conditions was done to establish a wide vocabulary for feature based description. Classification based on topology and form was done and prototype constraint relations were implemented to differentiate between some features. A feature is created from a topological group by computing points and interpolating them with uniform rational B-spline patches. Control points needed to compute the patches are computed from the interpolation points by an inverse relation. A designer-oriented modeling language, based on simple English syntax, was devised to specify procedures to be executed by the modeler in order to create features using minimal user input.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1989

Author dc:creator

• Gandhi, Ashit R.

Chair dc:contributor.committeechair

• Myklebust, Arvid

Committee members dc:contributor.committeemember

• Deisenroth, Michael P.
• Fries, Robert H.
• Mahan, J.R.
• Reinholtz, Charles F.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/54359

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/54359