Rulers were the most important part of engineering. Before we had cad software, we were drafting using t-squares and set squares. If you had that manual drafting course you will get what it was like and be thankful to AutoCAD. But on the other hand it was real art to draw that drawings by hand. If you are really good at you may draft as fast as you can do at CAD but the main disadvantage with hand drafting is that you can’t do the revisions easily as you do in cad.
In cad world we also have another big tool. This is copy paste. With pencil and sheet you can’t draw as quickly as in cad because in cad you can draft an already drafted part in seconds. Furthermore, you may create your own drawing libraries. These libraries are really beneficial if you are continuously drafting similar objects. And that feature you can’t beat by hand drafting.
Another development that made hand drafting out of the game is 3d modelling. With 3d modelling you can now see the part in real 3 dimension. Then you can easily get 2d drawing with several clicks in minutes. And if you don’t like any part of it you can review in seconds and your 2d drawing will reflect at the same time.
With 3d modelling and increase demand in cad software this technical art started to be forgotten. The beauty of it, may be only people who experienced will be able to understand.