Scanning vs. Digitizing
Erich Anderson
I work for a medium size public university in Texas. We want to get our
buildings' floor plans in electronic form, and then overlay the HVAC
ductwork (and other building systems) mostly for reference for the
maintenance and HVAC guys. We trying to decide whether to have the existing
blueprints scanned, most likely by an outside CAD company, or just purchase
a 3' x 4' digitizer and digitize the drawings ourselves.
Of course, a digitizing tablet is much cheaper than a large-format scanner
(about $1,200 for a digitizer versus $5,000 and up for a scanner). The
final drawings don't need to be very detailed or dimensionally accurate -
they just need to show the location of stuff hidden in the wall and above
the ceilings.
My concern is that scanned files will contain a lot of extraneous
information that will have to be cleaned up before we can use the scan. It
seems to me it would be simpler (and faster) to digitize the blueprint to
get the building perimeter and inside walls, and go from there. Also, the
boss doesn't like the idea of us using the outside CAD contractor - he
wants to keep it in-house as much as possible. And yes, the physical plant
does have a CAD draftsmen, but he is apparently quite busy and doesn't have
time for our project. The outside contractor wants $10 per sheet to scan
the prints, or $70 per sheet to scan them and clean them up.
If anyone out there has experience with this sort of problem, I'd like to
hear about it. Thanks for your help.
Erich Anderson
JAS - Global Village
Erich Anderson wrote:
>
> I work for a medium size public university in Texas. We want to get our
> buildings' floor plans in electronic form, and then overlay the HVAC
> ductwork (and other building systems) mostly for reference for the
> maintenance and HVAC guys. We trying to decide whether to have the existing
> blueprints scanned, most likely by an outside CAD company, or just purchase
>
> Erich Anderson
I'd suggest you get the Engineering Dept send out their student surveyors
and survey the campus. Then have your student drafters draft it up.
--
JAS
mailto:j...@shocking.com
http://www.shocking.com/~jas
Scott Drager
I used to work for an Architect and we tried that. We sent them to be
scanned and it didn't work out very well. (this was years ago tho) We
ended up getting a 3' x 4' digitizer and tracing them. That worked out
quite well.
Scott Drager
Don Jacobsen
> My concern is that scanned files will contain a lot of extraneous
> information that will have to be cleaned up before we can use the scan. It
> seems to me it would be simpler (and faster) to digitize the blueprint to
> get the building perimeter and inside walls, and go from there. Also, the
> boss doesn't like the idea of us using the outside CAD contractor - he
> If anyone out there has experience with this sort of problem, I'd like to
> hear about it. Thanks for your help.
Hi Erich
We just started scanning some of our drawings where I work. There
really isn't to much "clean-up" involved with them. We have found that
instead of running sepias or bluelines thru the scanner we get a black
and white copy made of the drawing (we have a full sized copier for
this) then run the copy thru the scanner. Also, if you get the setting
right on the scanner, you should be able to get good quality scans. If
you scan the drawings then you need the software to edit them. We use
Cad Overlay ESP for this. The draw back is it is pretty expensive
software. So now you have to add up the cost of a scanner and a
raster/vector editing program. It is much faster to scan a drawing than
it is to redraw it or digitize it. You need to look at how many
drawings you have and the amount of information that is on them and come
up with an estimate of how long it would take a person who gets paid X
amount of dollars per hour to digitize them. Compare that to the cost
of a scanner and the software. If you have a lot of drawings it may be
cost effective to get the scanner. Like I said, once you get the
settings on the scanner set right the scanning goes very quickly.
So far I have been pretty impressed with the quality of the scanned
images we have gotten
Don
G Rajesh
"Erich Anderson" <eric...@airmail.net> wrote:
> I work for a medium size public university in Texas. We want to get our
>buildings' floor plans in electronic form, and then overlay the HVAC
>ductwork (and other building systems) mostly for reference for the
>maintenance and HVAC guys. We trying to decide whether to have the existing
>blueprints scanned, most likely by an outside CAD company, or just purchase
>a 3' x 4' digitizer and digitize the drawings ourselves.
>Of course, a digitizing tablet is much cheaper than a large-format scanner
>(about $1,200 for a digitizer versus $5,000 and up for a scanner). The
>final drawings don't need to be very detailed or dimensionally accurate -
>they just need to show the location of stuff hidden in the wall and above
>the ceilings.
> My concern is that scanned files will contain a lot of extraneous
>information that will have to be cleaned up before we can use the scan. It
>seems to me it would be simpler (and faster) to digitize the blueprint to
>get the building perimeter and inside walls, and go from there. Also, the
>boss doesn't like the idea of us using the outside CAD contractor - he
>wants to keep it in-house as much as possible. And yes, the physical plant
>does have a CAD draftsmen, but he is apparently quite busy and doesn't have
>time for our project. The outside contractor wants $10 per sheet to scan
>the prints, or $70 per sheet to scan them and clean them up.
> If anyone out there has experience with this sort of problem, I'd like to
>hear about it. Thanks for your help.
>
>Erich Anderson
>
Erich,
Instead of going the Digitiser way for a short duration , I would prefer
a going the Scanner way. You can have a raster to vector programming
addon on top of Autocad so that it will help you in future.
Even if a single sensor goes in the digitiser then you are gone with the
investment.
But it is now upto you.
G.Rajesh
//Autodesk Product Support on the Internet//
Rusty Gesner
There was a pretty comprehensive article on this subject in a fairly
recent CADENCE (I think, or maybe CADalyst) magazine.
--
B. Rustin (Rusty) Gesner -- Group A
AutoCAD Expert.Consultant.Author.Editor
Co-author of Maximizing AutoCAD R13
See http://www.group-a.com/~rusty
ernest
On 26 Nov 1996 18:13:29 GMT, "Erich Anderson" <eric...@airmail.net>
wrote:
> I work for a medium size public university in Texas. We want to get our
>buildings' floor plans in electronic form, and then overlay the HVAC
>ductwork (and other building systems) mostly for reference for the
>maintenance and HVAC guys. We trying to decide whether to have the existing
>blueprints scanned, most likely by an outside CAD company, or just purchase
>a 3' x 4' digitizer and digitize the drawings ourselves.
>Of course, a digitizing tablet is much cheaper than a large-format scanner
>(about $1,200 for a digitizer versus $5,000 and up for a scanner). The
>final drawings don't need to be very detailed or dimensionally accurate -
>they just need to show the location of stuff hidden in the wall and above
>the ceilings.
> My concern is that scanned files will contain a lot of extraneous
>information that will have to be cleaned up before we can use the scan. It
>seems to me it would be simpler (and faster) to digitize the blueprint to
>get the building perimeter and inside walls, and go from there. Also, the
>boss doesn't like the idea of us using the outside CAD contractor - he
>wants to keep it in-house as much as possible. And yes, the physical plant
>does have a CAD draftsmen, but he is apparently quite busy and doesn't have
>time for our project. The outside contractor wants $10 per sheet to scan
>the prints, or $70 per sheet to scan them and clean them up.
> If anyone out there has experience with this sort of problem, I'd like to
>hear about it. Thanks for your help.
>
>Erich Anderson
I tried scanning one year ago and the result was not too good. As you
supose there was a lot of cleaning up before and after vectorising.
It depands a lot on what kind of plans you work with and how compex
they are. The more detail the harder to scan and work with it.
I guess the way I would try next is to let the plans be scanned and
purchease a good software package to edit them and vectorise them by
myself. This has two advantages:
1. You dont have to buy a expensive scanner and letting plans beiing
scanned is not too costfull
2. You have the control of the most critical part:
cleaning, converting to vector format, combining vector and raster
if desired (can be usefull !)
Anyway it is hard to get results you may expect so watch for best
solution with care.
Ernest