Research Of Three Dimensional Modeling Method Based On Sketch

Nowadays the mainstream of 3d modeling systems are usually with complex operation, long modeling period and difficult to realize natural interactions with people, thus the research of 3d modeling system based on sketch, which has important academic value and wide application prospect, become people's focus. At present there are some signifficant researches about sketch modeling carried out from aborad, domestic relevant study is still comparatively rare. Regarding the key problems occurred during the sketch-based 3d modeling process, that is , how to obtain automatic explaination from users'input sketch, this paper carries out the research of the methods to build 3d models based sketch.The main works and the characteristics of this thesis are as follows:1. Aim at the problems such as illegibility due to the abnormity of user input, bring about a preprocess and interpret method of sketch strokes. This method can obtain substrokes which contains certain information and normalized point list from users'sketch strokes, which is separately convenient for the stroke recognition operation in following work and the generation of 3d meshes with uniform, smooth and under-control density.2. Against to the problem that how to realize automatic interpret of engineering models from strokes, a method of Engineering Modeling based on sketch is purposed, this method can obtain proper parameter information from users'sketch input and then achieve automatic engineer interpret which meet to users'input intention. This method makes up the insufficiency of former 3d model systems that it is necessary to know the exact parameter to build 3d models.3. A method of Special Free From Modeling based on sketch is purposed. This method use fitted strokes obtained from the operation of curve fitting as input, through the introduction of interior point method, rotation method, and sweep method and other construction methods, and special objects'transcendental knowledge, we can generate special objects'free form 3d grid models. By the graphical display interface developed with OpenGL, we can add illumination rendering and texture mapping to these meshes and display corresponding 3d models with reality.