CAD lets the user choose, but the popular option is the ISO/DIN line weight and color coding system, which can be found on the ID band of drafting pens.
Cad is nothing but computer aided designing. It is very much useful in civil and manufacturing departments. Red, blue and green are standard colors. Line weights are weight of the line.
In a CAD system, colors are most commonly used to represent line weights. It contains the following colors as standard colors Magenta, White, Yellow, Red/Brown, Cyan/Blue, Green.
Well the standard colors are actually red and blue. The line weights consist of differing lines in level of thickness. If you want to know about all of them, then go to free auto cad tutorials in google.
