With advances in technology it is much easier to create digital artwork. Back when my husband and I worked as illustrators fresh out of Sheridan College's Illustration program, there were no computers. Everything was drawn by hand using technical pens and guides. These skills became valuable assets when the digital world sprang up. Edit Undo was your best friend and you didn't need to feverishly scrape and erase away mistakes.
One of the first programs I learned to use was Autocad which gave me the knowledge to use cad files for projects and illustrations that I was creating in CorelDraw. Cad files could easily be imported into Corel and be used as reference to accurately produce drawings to mechanical specifications. Isometric drawings were illustrations drawn in a 33 degree perspective. This allowed parts of the drawing to be flipped horizontally and vertically without having to redraw certain parts. The example below shows how the same desk drawing was used to show two views without having to redraw it.
Other reference that was used were photographs of the actual components taken with a ruler beside it so you could accurately measure them in the final illustration. In the aerospace business where we worked for many years it was cruicial that illustrations were accurate. Mechanical specifications from parts lists and colour specs from Federal Standard Colour books were also necessary to accurately replicate the actual hardware.
There are a few standards that need to be kept when illustrating in a draw program and they are:
Decide on 3 lineweights that you will use. One line weight for the outside, one for the main internal lines and one thin line weight for the details.
Test the line weights so they are all visible and make sure they stay consitant when scaled up and down.
If using dotted lines for exploded views decide on a consistant line throughout your drawings.
In another blog I will discuss tips on how to use the different computer draw programs like Adobe Illustrator and CorelDraw but for now this should get you started.