#Scanning Drawings???
6 messages in this thread
Dave, That all sounds workable – thanks! Now, what about the scanners
themselves. Page Scanners (8.5×11) are relatively cheap (less than $2000)
but how about D and E size scanners?
I do need to make sure the company realizes that everything will be a
"converted" drawing which is different from the original hand drawn (or
hand entered) drawing as someone else has pointed out. I assume that these
conversion programs would work something like Corel System's Corel Trace
program in that it reads in an image and gives a representation of the
original. With that representation you can then clean up or even "better"
the original drawing…
I also am assuming that the conversion process works on a TIFF file format
or some other graphic representation of the drawing. Is that correct?
Again, I am familiar with page scanners, not larger ones…
Thanks Dave, any further help is appreciated!
Owen
Owen – unless you have a LOT of large-doc scanning to do, I'd recommend using
a service bureau. I use a Houston Instruments Scan-Cad which is a teeny
little device (smaller than a hand scanner) but which attaches to the pen
holder of my HI plotter, allowing me to scan drawings as large as my plotter
can take. The plotter rolls the original back and forth, while the penholder
moves the scan head a sideways step at a time. The software that comes with
it automatically stitches the strips together.
It does an excellent job, but it is SLOW! It takes about 15-20 minutes to
scan a D-size drawing at 200dpi (incidentally, it's rarely worth scanning at
a higher res than this, if your aim is drawing conversion). Two years ago, I
paid about $6k for the Scancad, but I live in Canada, so if you're in the
states, you'd probably be looking at about $1,000 less.
A dedicated scanner, like Houston Instruments's LDS4000+ costs about twice as
much, but if you're dealing with volume, it's many times more than twice as
fast. The other big name in large document scanners is Contex. Prices are
comparable, and you can choose a D-size or E-size unit (the LDS is E-size
only).
As Ang pointed out, you should be prepared to do a substantial amount of
editing on your automatically-vectorized drawing. Everything will be on one
layer, and text comes through as lines and arcs. Using CAD Overlay is more
work up front (you recreate the drawing in AutoCAD on top of the scanned
image), but you won't have that often messy cleanup at the end.
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I don't know of any programs that convert TIFs to DXB directly (although
there are plenty of format conversion programs that convert, say, TIF to
PCX). CAD Overlay only handles RLC scan files, but includes a utility to
convert from TIF to RLC. Draftsman will convert either RLC or PCX.
There was an article in Cadence about a year ago about someone using one of
the DTP conversion programs, but I can't remember if it was Corel Trace or
Adobe Streamline or something else. Should work ok, though.
Dave
Thanks Dave.
I believe the picture is coming in clearer now. The guys doing the work
would probably be frustrated with editing an image they would "expect" to
be right already…
What about these service bureaus? Is there a listing of them somewhere?
I'm in central North Carolina for what it's worth… What do they charge
(approx) per image and do they do the full conversion/cleanup???
Thanks a bunch for your help in this,
Owen
Owen… I don't know of any particular service bureaus down your way. You
could check in the back pages of Cadalyst or Cadence for listings. Another
possibility is to contact the vendors and find out who sells them locally;
the latter could put you in touch with local service bureaus.
For the Houston Instruments LDS4000+, call 800.444.3425. Contex scanners are
marketed by both Vemco and Ideal, but I can't find a number for either. You
could try back issues of the CAD mags if you have any.
Dave
Thanks Dave. You guys have been great! I will find some CAD rags and find
the numbers. At least now I know what I am looking for and have a
conceptual understanding of how it all works…
Thanks again,
OGS