Plotter as digitizer

Could you use a large format document scanner and capture your drawings to pdf?

--Winston

It would have to be a *really* big scanner (or, a photographic process) as E size drawings would humble my *B* size scanner!

And, I suspect it would be hard to extract the geometric data from the PDF -- unless I wrote something to analyze the image contained therein, itself.

(I.e., I want to be able to *use* the data represented in the drawings, not just "view" it)

Hey, Don.

Ah.

Large format scanners are available:

...or DAGS "E size scanner"

Perhaps your local Kinko's can rent you one for reasonable money.

From there you need a program to convert it's output to a DXF.

And a *lot* of cleanup after that!

--------OR-----------

There are service bureaus that will manually capture your print to a CAD file for $75. an hour!

--------OR-----------

You can be sure there is a talented young person around who would leap at the chance to make $50 each to manually capture each of your prints, after a few free tutorial sessions.

--Winston

It sounds like just making a bitmap isn't good enough; you want to maintain connectivity. If I've guessed right, then the only thing I can really think of is to shove your probe around by hand, and trace the wires; this would only work if your plotter can actually read back its pen's position, and you have some SW following it that understands connections.

Other than that, I've got nothing but political propaganda, but that gets me shunned. ;-)

Good Luck! Rich

Yes. E.g., the plans for the house would be helpful to have in CAD as it would make an easy job of determining how many sheets of wallboard I will need to hang, how many (floor) tiles to lay, etc. Much easier (and safer!) than trusting a tape rule :-/ (damn things *lie* every time I use one!)

Also, there are things you can do with a dimensionally accurate drawing that are *really* tedious to do, otherwise. E.g., deciding where to lay the *first* floor tile to yield the best "pattern" throughout the house!

Gack! I'm already grumbling about having the damn plotters taking up space in the garage -- and you want me to add another dust catcher? :>

Yes. And, never knowing if an error hasn't crept in.

I was thinking about this on my evening walk and think I have come up with a solution -- when the problem defies solution, *change* the problem! :>

I can, instead, write an *emulator* that allows the plotter to masquerade as a conventional digitizing tablet (e.g., a Kurta, Calcomp, Summagraphics, etc.). This allows me to use the plotter with a variety of software programs instead of just, e.g., AutoCAD.

The issue then becomes one of finding the digitizer that is supported by the "most" tools that I am likely to use (so I don't have to write more than one "emulator")

Maybe I don't fully understand the problem.... Could you hang the plots on a wall and photograph them? Then, post-process those image files to get what you want?

What is it that you want to extract from the paper drawings, that must make it into your electronic copy? If accurate dimensions, you should be able to scale the photograph, assuming a few variables fall into place.

-mpm

Then, how do I get the *images* into, e.g., a CAD program? I.e., for the house plans, once in AutoCAD, I could lay a pattern of floor tiles onto it and use the "walls" to "trim" them. I could touch the corners of each room and have it report the area of the polygon. Etc.

I have *exactly* the same tapes.

(...)

Better you than me. :)

That is true for any approach one takes. One could find the disk files that one created initially.....

Just a thought. :)

(...)

My favoritest CAD program in the world, Rhino3D allows me to place a bitmap as 'wallpaper' on the screen.

I have used that capability to capture parts I've scanned by tracing CAD lines over the lines I see in the bitmap.

You see where I'm headed with that? :)

--Winston

Have someone scan it.

Get a quote and see what it costs.

Cheers

Well, not yet. But we still have hope.

I have learned that a length of *wire* (NOT "string" -- string stretches too much!) makes a better "ruler": "I need to cut the board to *this* length..."

:>

I wasn't the architect that drew the house plans! :>

I wonder how reliable that would be trying to scale a

50+ inch drawing to correspond with an on-screen image...

I'm currently looking at various tablets with an eye towards the simplest/cleanest implementation (e.g., any "smarts" in the tablet would have to be emulated correctly in anything I write). OTOH, that might make the design easier to implement

*if* I allow the transactions to drive the emulation instead of forcing the emulation to fit a specific model/configuration.

E.g., scan the input file and let it define the "size" of the (virtual) tablet that I am defining.

And I have learned that sometimes I work faster and more accurately when I *don't* measure.

Jig for cutting fence boards instead of measuring

Holding a board up to where it needs to go and scribing a cut line against where it needs to stop.

(...)

OIC

(...)

It is down to scanner resolution and careful alignment.

Just now for larfs, I created a rectangle measuring

100 feet by 100 feet so that I could zoom in to find out how much resolution I had for the minimum feature size for an underlying drawing.

It ran out of gas at about 14 *pico inches*. (note that the underlying bitmap would look like one enormous pixel near x=0 Y=0 at this magnification.)

I *love* Rhino3D.

At the end of the day, it will be you peering through crosshairs on a microscope attached to your pen holder, laboriously capturing vectors. You are made of stout stuff, Don. I couldn't do it. My back is sending me warning pains just thinking about it.

I would cheat and make a scanner do the hard work. :)

--Winston

Yup. Though even this way you have to remember that the pen won't mark *exactly* where the cut should be.

But you created that rectangle *in* the CAD program? I.e., using *it's* notion of what a "foot" might be.

In my case, I have a drawing drawn to *some* scale which has to be *mapped* into a corresponding scale inside the CAD program.

No, the "sight" is a ~1/4" diameter "pipe" made of lexan. All it really does is bring the image that is on the paper "under" the pen (sight) up to a point where it is visible to the user.

Recall that architectural drawings are lots of right angles (typically... there are a few exceptions, here) so the points that you are digitizing tend to be offset along one axis -- or the other -- from each other (no diagonals).

I have to think hard about how I want to handle the

*schematics*, though. It may be simpler just to redraw everything using symbol library is convenient (instead of trying to reproduce the drawings AS IS) *Big* plotter. It stands ~4 ft tall so the sight is pretty much where you can just look at it casually.

There is a large Calcomp tablet in a local auction next week. If I can figure out an easy way to get it home, I may opt for that, instead.

Depending on where home is for you, I might be closer. I have an HP DraftPro Plus (E-Size, 8-pen carosel plotter) plus several hundered unused pens I would glady part with for the right price. And by that, I would suggest half the price of a new wide-angle 35mm lens, or about $200.

Mine does not have (what I assume is an optional) digitizer pen, but maybe they are available. BTW - This plotter is in great shape, with probably less than 300 hours on it total. Parallel port interface.

-mpm

--
Since you want to discard the drawings once they've been digitized,
perhaps you could cut them up into "B" sized chunks, scan them to
.pdf, convert them to .dwf with something like AcroPlot Pro,

http://www.cadzation.com/acroplotpro_info.htm

then snap all of the .dwfs back into a single big drawing?

Architectural drawings aren't the exact dimensions of the finished building. I've seen walls that were off by more than a foot from the blueprints. Sometimes there are 'As Built' drawings to match the actual construction, but they are rare.

Architectural drawings don't show you were the studs are in the framing, so you can end up using extra sheets of drywall to avoid more tape & mud on joints.

--
You can't have a sense of humor, if you have no sense.

Not to mention out-of-square (or plumb) walls. I doubt there is an "as built" drawing of many of these.

When I do a room, I do add these to the CAD drawings. It helps later.

One place I worked, the owner built an addition. One wall ended up

16" shorter than the opposite because he measured the stakes wrong, then poured the foundation out of square.

--
You can't have a sense of humor, if you have no sense.

I hope it was a "modern" house. At least he saved a stud. ;-)