Greg Farris wrote:
Done properly, PDF files should be just as zoomable as the AutoCad
originals.

What happens when you create a pdf from an AutoCad drawing, using Adobe's
"distiller" is not the same as the scanned raster images we're talking about
- it's more that line thicknesses do not scale correctly with your zoom
factor. If you zoom 1000% on your AutoCad drawing, simple lines are still one
pixel in width. You can see all the detail you want.

Ah, now I understand what you're getting at. The "zoom" feature in AutoCad
is not a photographic/geometric zoom, it's a scale change. It's like
looking at a terminal chart, a sectional, and a WAC of the same area. Some
things have been scaled (i.e. the distance between geographic features),
and some have not (the size of a VOR compass rose).

That's a much higher level concept than raster vs. vector graphics. In
AutoCad, the entire vector graphics representation is regenerated from
AutoCad's internal object model each time you change the scale.