Constrained shape scaling of trimmed NURBS surfaces

Pifu Zhang, Caiming Zhang, Fuhua (Frank) Cheng

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

7 Scopus citations


A method to scale and deform a trimmed NURBS surface while holding the shape and size of specific features (trimming curves) unchanged is presented. The new surface is formed by scaling the given surface according to the scaling requirement first; and then attaching the (original) features to the scaled NURBS surface at appropriate locations. The attaching process requires several geometric operations and constrained free-form surface deformation. The resulting surface has the same features as the original surface and same boundary curves as the scaled surface while reflecting the shape and curvature distribution of the scaled surface. This is achieved by minimizing a shape-preserving objective function which covers all the factors in the deformation process such as bending, stretching and spring effects. The resulting surface maintains a NURBS representation and, hence, is compatible with most of the current data-exchange standards. Test results oh several car parts with trimming curves are inncluded. The quality of the resulting surfaces is examined using the highlight line model.

Original languageEnglish
Title of host publication11th International Conference on Design Theory and Methodology
Number of pages10
ISBN (Electronic)9780791819739
StatePublished - 1999
EventASME 1999 Design Engineering Technical Conferences, DETC 1999 - Las Vegas, United States
Duration: Sep 12 1999Sep 16 1999

Publication series

NameProceedings of the ASME Design Engineering Technical Conference


ConferenceASME 1999 Design Engineering Technical Conferences, DETC 1999
Country/TerritoryUnited States
CityLas Vegas

Bibliographical note

Publisher Copyright:
© 1999 American Society of Mechanical Engineers (ASME). All rights reserved.


  • Constrained deformation
  • Constrained scaling
  • NURBS surfaces
  • Strain energy
  • Trimming curves

ASJC Scopus subject areas

  • Mechanical Engineering
  • Computer Graphics and Computer-Aided Design
  • Computer Science Applications
  • Modeling and Simulation


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