Deformation of objects with non-linear constraints

Abstract

There are various techniques for deforming three-dimensional objects in existing computer-aided design (CAD) systems. To maintain user-specified constraints in the deformation of a parametric and feature-based model is a new challenge in deformation modelling. This article presents a constraint-based deformation technique. Firstly, a deformed object is obtained with common deformation techniques such as free-form deformation (FFD) and axial deformation. Secondly, features defined with parametric are grouped into systems of primitive constraints based on user specification. Finally, features are reconstructed by the use of optimisation technique. The optimisation is to minimise the changes in the deformed model subjected to all the provided constraints. This method allows deformations like FFD and axial deformation to be performed without destroying the constraints in the model. This method combines the advantage of free-form modelling with feature-based modelling and allows engineering design to be performed in a free-form manner.

Keywords:

• CAD/computer-aided manufacturing (CAM)
• optimisation
• mesh editing
• engineering feature

Acknowledgements

This work is partially supported by a grant from the University Grant Council of the Hong Kong Special Administrative Region (No. 412508) and by a Direct Grant (No. 2050492) from the Chinese University of Hong Kong.