Employing the oblique projection shifting method , we have solved some graphic problem in descriptive geometry . it is very simple and fruitful to deal with difficult problems in orthographic drawing 摘要介绍了投影变换中的斜投射法及其在解决工程图学一些问题中的应用。用这种方法可解决工程图学中用正投影方法不便解决的图示、图解问题，而且具有应用范围广、作图简便的优点。
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From the practical view , this paper summarizes the theory of orthogonal projection based on the first - angle projection , the ways of manual reading drawings and discusses the problems relevant . the mechanism similar with csg is used to reconstruct 3d object with priority to csg and aid by b - rep 本文从实用的角度出发，总结了正投影工程图中的投影理论基础、人工读图方法以及注意的相关问题，采用了以csg方法为主， b ? rep方法为辅，类似于csg建模的机制来实现二维视图的三维重建过程。
