We want a map!

[Redrobes]

Just get google maps out, find some big factory and trace over the buildings. You might have to stretch or chop to make it fit with your sewer piping but on the whole its just boxes. If its a really big factory then some of the big car plants should be good.

Put :-

42.302325,-83.16453
52.428702,-1.929753
43.626726,1.35222

into google maps.

[Hoel]

I've worked at a pretty big factory, Volvo Powertrain (makes the BIG engines). I'd say it would be a real pain to map it realistically. The nice looking boxes you see from the outside are just honeycombed with walls, rooms, and big machines. Even the open spaces are full of struts, girders, pillars, railings and multiple levels, half levels and sub spaces. You could get lost for days if the doors weren't kept locked to prevent it.
When I GM and my players enter any kind of industrial facility, I pull some fireplan from the web or just descibe it to them til they are lost, because that's what I got the first few weeks...