我们的伟大领袖毛主席教导我们说:“社会实践的继续,使人们在实践中引起感觉和印象的东西反复了多次,于是在人们的脑子里生起了一个认识过程中的突变(即飞跃),产生了概念。”对方体画线工作来说,一个是求出展开图,另一个是求出加工成形用的两面角——要依此作出卡样板。历来的作法,都是将这两个问题依投影放大样的途径分别解决。由于投影繁杂,需有较强的投影概念和相当熟练的作图基础,但这是不容易掌握的; Chairman Mao, our great leader, taught us: “The continuation of social practice has made people feel and impress in practice many times. As a result, there has been a sudden change in people’s minds (that is, a leap forward) , Resulting in the concept of ”the other body line drawing work, one is to find the expansion plan, and the other is to find the two sides forming angle processing - to be based on this card model. Historically, these two issues have been resolved separately by projection and amplification. Due to the complexity of the projection, a strong projection concept and a fairly proficient mapping basis are required, but this is not easy to grasp;