At the moment I illustrate
to spare part catalogues at
Volvo Construction Equipment.
As Technical Illustrator I have produced huge amount of assemblies and blow apart images. Main idea is to see the section in its environment assembled and blown apart.
The pre work has been done in 3D visualization software as Composer or Creo Illustrate. The cad comes assembled. Then illustrator creates assembled views including which references should be visible. After that the various blow apart sections are done. The mock up applying design and final layout is done in Illustrator.