The Research & Application On Object Composing Based On The Primitive Model Tree

Computer interpretation of engineering drawing is an subject which relates to engineering graphics, cognitive science, computer vision and computer information processing technology and so on. It will be a promise application in the area of CAD/CAM. However, it is clear that all the current relevant methods are far from the aim of practical application of computer interpretation. And according to the present instance of design and manufacture fields, engineering drawing interpretation owns a mass of markets and applications demands. Considering the dispersivity, covertness and fuzziness of drawing information, knowledge of data structure is utilized to build primitive model tree, based on which primitive information and composing information are dealt with for great effect in object composing in this thesis.In chapter 1, the history and development of engineering drawing interpretation are reviewed, at the same time the existing problems are analyzed and then the content of this thesis is introduced.In chapter 2, a primitive model tree based on four different shape character sort of part is brought forward. Based on four different shape character sort of part, four different frames of the primitive model tree laid out. The primitive model tree is built by the dimension tree which is built by choosing datum dimension based on four different frames of the primitive model tree.In chapter 3, a technology which manages the primitive information in the primitive model tree is discussed. Traversing the primitive model tree the primitive relation, parent ,children and sibling of primitive is found, and relation of which is judged and deposited. The primitive empty or solid characteristic is judged based on primitive relation and is deposited.In chapter 4, a method which manages composing information in the primitive model tree is researched. The influence of the conversion of the primitive relation and the adjustment of the primitive position and shape for composing information in the primitive model tree is discussed. And a technology of the sequence of creating primitive in course of object composing is advanced based on the primitive tree in the end.In chapter 5, the prototype system of drawing interpretation is developed, and some examples are given.In chapter 6, the work of this thesis is summarized, and the further research work is put forward.