Constraints Based Deformation

There are various techniques for deforming three-dimensional objects in existing CAD systems. To maintain some user specified constraints in a deformation of a parametric and feature-based model is a new aspect in deformation modeling. This paper presents a constraints based deformation technique. Firstly, a deformed object is obtained by some common deformation techniques such as FFD, axial deformation. Secondly, parametric features are grouped into systems of primitive constraints based on user specification. Finally, parametric features are reconstructed by the use of optimization technique. The optimization is to minimize 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 original constraints in the model. In order to maintain some particular feature in a model, users may need to specify features with a combination of primitive constraints. This method combine the advantage of free-form modeling with feature based modeling system, and allows engineering design to be performed in a free-form manner.