Symbols used to define a projection method and a cartesian coordinate system for a three-dimensional space

Abstract

The important task becomes not the creation of the drawing but the interpretation of the drawing. So using correct fundamentals for the projection method is cornerstone. Arrangement of the front and the left side views is regulated by graphical symbols for the indication of a projection method according to ISO 128-30:2001(E). Still we can find different examples of symbols used to define a projection method when arrangement of the front and the right side views is regulated. What does this difference in accordance to a Cartesian coordinate system for a three-dimensional space mean? It means to place an object into different octants. In the first case the object will be placed into the first octant (first angle method) or the seventh octant (third angle method). In the second case the object will be placed into the fifth octant (first angle method) or the third octant (third angle method). I have been interested in this problem for quite some time. In my opinion it is best for a multiview drawing to place the object into the first octant. I would like to invite colleagues for a discussion about the possibility of using the same projection method or clearly defining in which octants the objects must be placed.