Re-using as-built cad drawings, or cad drawings supplied by manufacturers and external designers can be a real source of frustration. You want to re-use the graphical geometry so you don't have to redraw it. But the CAD properties don't conform with what you are used to or need in your field of practice. This makes these drawings excruciatingly slow to work with, your production tools can't be used on them, and there will be a frequency of errors on the printout such that you are tempted to m...