Before I learnt to use ISOdraw, my illustrations were done by hand and scanned. These are a few very old examples of scanned ink work (below)

A few examples of the kind of illustrations that would be published in the maintenance and repair manuals, such as closer details, removal and replacement, and attaching parts. Most illustrations are done with the aid of engineering drawings and photographs (below)

A few examples of the type of illustrations that would be published in a parts catalogue, such as exploded views with attaching parts. Most illustrations are done with the aid of engineering drawings (below).

Cut-away illustrations done in IsoDraw for technical manuals or training charts showing where main components are situated on and inside the vehicle (below).