Three-dimensional Geometric Model Simplification

Nowadays, along with the development in computer graphics, more and more applications other science fields require analysis and display of 3D geometric models. Commonly, because of the large-scale data quantity of a 3D geometric model, it is very difficult to store it, to transfer it and to render it. But in many cases, the purpose of manipulating on a 3D geometric model is just to display it, so a simpler model whose shape is similar to that of its original model is usually enough. And also, using a simpler model is beneficial to quicken scene's rendering and to save more space of storage. So, it is necessary and significant to research on the algorithm of simplifying a complex 3D geometric model.After analyzed and studied on some algorithms about how to simplify a complex 3D geometric model from home and abroad, this paper proposes the concept of divisional envelope pitch and ameliorates the method of envelope's conformation proposed by Cohen using the dichotomy in linear search. When a triangle is selected and contracted tentatively, two corresponding divisional envelope pitches should be constructed at first. The divisional envelope pitch is a bit of the whole simplification envelope. So, with the help of the divisional envelope pitch, lots of unnecessary detection of triangles intersection won't be carried out. And it speed the process of model simplification.At last, this paper has developed a demo system to verify this algorithm. The results from experiment show that the simplified-model by the algorithm of divisional envelope pitches can preserve the sharp features and be of a higher resemblance with its original geometric model.