Research And Implementation Of Automatic Dimensioning Based On Solid Synthesis

Automatic dimensioning on engineering drawings is an important subject in CAD. Based on primitive solid synthesizing, a method of extracting primitive solid from feature model is studied, and a method of distributing, adjusting dimensions in each view is advanced, thus correct and distinct dimensioning can be obtained.The main work of the dissertation is as follows:In chapter 1, the meaning of automatic dimensioning is discussed, the status of the subject is analyzed, and the study routes and contents of this dissertation is explained.In chapter 2, according to primitive solid synthesizing, information of primitive solid, which compose the feature model, is obtained. And the types of primitive solid are confirmed by matching the information with the feature in feature library. Then the dimension model generated by another relative system is obtained.In chapter 3, dimensions are classified to four sets made up of several subsets by their types, directions and areas. Then dimensions, which are distributed to the set and the subset by their positions, are adaptively adjusted in each set or subset according to the synthetical status of primitive solid which are restricted by the dimensions.In chapter 4, the distributing of dimensions in each subset are adjusted so that all the dimensions can be expressed correctly and distinctly on engineering drawings. Dimensions can also be adjusted interactively if necessary.In chapter 5, the structure of prototype system is presented, and some examples of automatic dimensioning are given.In chapter 6, the work of this paper is summarized and the future research work is put forword.