Level-set Based Offset Method For Mesh Models With Feature Preservation

Offsetting Surface is one of the most important operations in Computer AidedDesign and Computer Aided Manufacturing. It is also important in fast prototype,coordinate measuring machines, robot collision avoidance and so on. Level setbased method as implicit surface is an efficient method to deal with mesh models.The thesis presents a novel method for offsetting mesh surface by level set methodwith feature preservation.Level set method avoids self-intersection instinctively in the progress of theimplicit surface evolution. When achieving the algorithm, we use DT-Grid datastructure, which is a level set data structure and has efficient performance in timeand memory dissipation when level set surface evolves. So this method is of abilitywhen offsetting large mesh models with high-resolution. Our method is made up ofthree steps. The first step is level set initialization. Mesh model is converted toimplicit surface by using closet point method. The second step is level set evolution.After building level set equation for offsetting, what we should do is to computelevel set equation and reinitialize when necessary. The last step is mesh extraction.We use modified marching cubes method to extract mesh surface from implicitsurface representation and save as explicit surface representation. In the meshextraction, we present a new method with is combined with removing ambiguity andpreserving sharp features. At last, we take some experiments in several mesh modelsand get desired results. That proves this method is practical and feasible.