Study On Completeness Testing Of Dimensioning In 2d Drawing

Dimension work is a considerably important link in the whole progress of Engineering Drawing. Its correctness for products' design is very important. However, all the check-up to dimension is by designers'handwork in conventional method. If dimension of drawing is relatively simple designers'check-up work is enough. But if dimension of drawing is relatively complex, designers' check-up work which may cause mistake and miss taking place is not enough. So, how to check up dimension system automatic is one significant thing. This dissertation mainly discusses how to automatically check up the deficiency and redundancy of dimension of multi-views in two-dimension of engineering drawing.Some methods are put forward to check up dimension system, but they only for one view but not multi-views in two-dimension of engineering drawing. This dissertation discusses and analyzes experts'correlative work, and quotes 3D reconstruction to present a spatial model, which changed from dimension system of engineering drawing. In our approach, the screen coordinates of different views in a part drawing are converted to an unique space coordinate, and check up the dimension completeness by the principle based graph theory and artificial intelligence route search technology.In order to realize this principle, a method is designed which presented for segmenting engineering drawings into views and establishing the corresponding relations of coordinates between them. Two sets of 2.5D coordinate systems are introduced as intermediates to relate the 2D original drawing system to the 3D space projection coordinates, and a formal technique is developed for constructing transformation matrices between coordinates. The nonlinear dimensioning schemes are decomposed into several sets of linear dimensions. And then the dimensions in the spatial model are changed to non-directed graph, at last testing whether the dimensions in the drawing are redundant or insufficient is carried out by traversing adjacent matrix of the non-directed graph. According to the theory, this dissertation completes a sampling system to validate the rightness and the availability of the new resolution method by check up dimension of engineering drawing in different views.