透视仪的研究

STUDYING AND MANUFACTURE OF PERSPECTIVE DRAWING MACHINE

绘制透视图是一种复杂的作图过程,特别是对未学过透视理论的广大技术人员,根本无法实现,既或学过透视理论的人,作图也实分困难。本文探讨一种新的作图方法,改变过去用辅助线求灭点(灭点一般都远离图板)再根据灭点求透视线的通常作法,而采用先选定灭点(灭点可选在图板边缘)后决定辅助线,从而减少了由于灭点在图板之外而造成的困难。这种方法是先根据选定的灭点求透视点,后作透视线。称这种方法为固定灭点法。根据固定灭点法设计的透视仪,可使未学过透视理论的人,只根据物体的正投影图,就可容易地画出各种情况的一点、两点和三点透视图。同时图板利用率高、绘图迅速、机构简单、使用方便。

Drawing perspective is a complexed procedure which is considered great difficult for those who have already studied perspective theory and even impossible for the many technicians who lack of the knowledge of theory. Contributed as a remedy, a new method for perspective is put forward in this paper. It first adopted vanishing point (may be oriented right at the edge of the drawing board) and then delineates auxiliary lines; differential from the conventional method in which generally vanishing points are first found with the aid of auxiliary lines (usually vanishing point are far away from the board) and the perspective lines are delineated thereafter. So in this Procedure the problem caused by that vanishing point is out of the board will be avoided. Because this method helps us to delineate the perspective lines secondarily and find perspective points with vanishing points first,it is named as 'Method of Fixed Vanishing Point'.With a perspective drawing machine designed in accordance with the procedure, one can easily delineate, even without the Knowledge of perspective theory. The machine, also helps to make a good use for the drawing board and the perspective accuracy is high, meanwhile it is simple in make and easy in use.