In china , the first - angle projection is adopted preferencially following related national standards 国家标准规定,我国优先采用第一角画法绘制机件的图样。
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。