Author Topic: Scaling a plotted drawing??  (Read 22359 times)

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CADaver

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Scaling a plotted drawing??
« on: June 28, 2004, 01:02:37 PM »
IMMHO
Information that is necessary to construct the elements depicted in a drawing must be derived from the content of the drawing, not from laying a plastic stick on a wadded up coffee stained 3rd generation print in the field.  Scaling a drawing is, at best, a bad guess that asssumes a level of accuracy exists is completely uncontrollable by any one indivdual.

MSTG007

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Scaling a plotted drawing??
« Reply #1 on: June 28, 2004, 01:08:22 PM »
true.... its close.. but not exact
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Dent Cermak

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Scaling a plotted drawing??
« Reply #2 on: June 28, 2004, 01:10:50 PM »
Once a paper copy goes outside, the scale is pretty much gone.Set a paper copy outside (especially in the South) and leave it for 30 minutes. Then check the scale. You will be surprised. Kinda like expecting a blur print to be to scale. (yea, right, rolling a sheet of paper around a glass cylinder while shinning a hot, bright light on it and blowing ammonia fumes on it will produce a scale copy.)
Only a few ways to get a true scaled copy. Contact photo print on 7mil stable base mylar or a correctly produced e-copy. I can burn you a scaled blue line using a flat bed exposure unit wit a glass lid and a big ole vaccuum pump, but once you walk outside, all bets are off.

CADaver

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Scaling a plotted drawing??
« Reply #3 on: June 28, 2004, 01:21:13 PM »
Quote from: MSTG007
true.... its close.. but not exact
Most often it's not even close.

CADaver

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Scaling a plotted drawing??
« Reply #4 on: June 28, 2004, 01:22:37 PM »
Quote from: Dent Cermak
Once a paper copy goes outside, the scale is pretty much gone.Set a paper copy outside (especially in the South) and leave it for 30 minutes. Then check the scale. You will be surprised. Kinda like expecting a blur print to be to scale. (yea, right, rolling a sheet of paper around a glass cylinder while shinning a hot, bright light on it and blowing ammonia fumes on it will produce a scale copy.)
Only a few ways to get a true scaled copy. Contact photo print on 7mil stable base mylar or a correctly produced e-copy. I can burn you a scaled blue line using a flat bed exposure unit wit a glass lid and a big ole vaccuum pump, but once you walk outside, all bets are off.
Even that assumes the plotter have been recently (and accurately) calibrated recently to plot to scale, and the media used to produce the plot was stable.

Dent Cermak

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Scaling a plotted drawing??
« Reply #5 on: June 28, 2004, 01:28:37 PM »
Plotter won't really do it. I'm going back to the
Golden Days" of the contact photo lab. Big ole vacuum frame, pin light, photo screen, 7mil Dupont film!! Ah!! the last days of accuracy.

M-dub

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Scaling a plotted drawing??
« Reply #6 on: June 28, 2004, 01:30:59 PM »
Just add dimensions to the drawing!  Who needs to draw to scale?!  :twisted:



*M-dub runs for cover*

CADaver

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Scaling a plotted drawing??
« Reply #7 on: June 28, 2004, 01:35:21 PM »
Quote from: Dent Cermak
Plotter won't really do it. I'm going back to the
Golden Days" of the contact photo lab. Big ole vacuum frame, pin light, photo screen, 7mil Dupont film!! Ah!! the last days of accuracy.
What was the source data media? you needed something to photo.

Keith™

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Scaling a plotted drawing??
« Reply #8 on: June 28, 2004, 01:38:41 PM »
Well, we do have a disclaimer note that basically states ... "When referencing these drawings, the printed dimensions override any scaled dimensions. Do not scale these drawings for dimensions."

Of course everyone scales the dang things.... so why not at least attempt to draw (and plot) them accurately.

Incedently we check our plotted drawings for scale factors on a routine basis.
A number of our contractors have also began having their construction plans laminated to prevent those coffee spills from damaging the plans in the field.
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CADaver

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Scaling a plotted drawing??
« Reply #9 on: June 28, 2004, 01:39:38 PM »
Quote from: M-dub
Just add dimensions to the drawing!  Who needs to draw to scale?!  :twisted:
*M-dub runs for cover*

Therein lies the confusion.  You saw PLOT to scale and thought it meant DRAW to scale. Two completely different aspects of production.  
"Drawing" to scale is required for accurate construcability, "plotting" to scale is not.  The accuracy of "drawing" produces accurate dimensions on that drawing.  The construct should be accomplished from the dimesions, not from laying a plastic stick along a plot.

Dent Cermak

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Scaling a plotted drawing??
« Reply #10 on: June 28, 2004, 01:46:42 PM »
Cadaver, in the "good ole days" we had our own aircraft and kelsh stereo plotters.We produced color separated maps for the Corps of Engineers. Did the photoghrapy (You haven't lived until you've processed a 500' roll of color film by hand!!) and all of the compilation in house. Then I'd get the data and do all of the engraving and lab work. Kept me busy and off the streets.
Source data then was the 7mil scribe coats. All photocopy was by contact print. All data had to be within 0.001" of compilation or it was rejected. All line widths had to be within 0.001" of standard or work was rejected. I still like to draw index contours at 0.008" anf intermediate contours at 0.004". Maybe this is why I am such a stickler on accuracy. In mapping we were held to the wall by stiff, exact standards. An idea of drawing layers never confused me. We used to call them "overlays". No real differance.

CADaver

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Scaling a plotted drawing??
« Reply #11 on: June 28, 2004, 01:53:50 PM »
Quote from: Dent Cermak
Cadaver, in the "good ole days" we had our own aircraft and kelsh stereo plotters.
Yikes, high-dollar hardware there.

Quote from: Dent Cermak
We produced color separated maps for the Corps of Engineers. Did the photoghrapy (You haven't lived until you've processed a 500' roll of color film by hand!!) and all of the compilation in house. Then I'd get the data and do all of the engraving and lab work. Kept me busy and off the streets.
Source data then was the 7mil scribe coats. All photocopy was by contact print. All data had to be within 0.001" of compilation or it was rejected. All line widths had to be within 0.001" of standard or work was rejected. I still like to draw index contours at 0.008" anf intermediate contours at 0.004". Maybe this is why I am such a stickler on accuracy. In mapping we were held to the wall by stiff, exact standards. An idea of drawing layers never confused me. We used to call them "overlays". No real differance.
I did a little bit of map work fo COE when I first got in the business, ink on mylar. I'm so glad I got out before having to do contact prints.

Dent Cermak

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Scaling a plotted drawing??
« Reply #12 on: June 28, 2004, 02:00:10 PM »
Contact prints were so much easier than the ink on mylar. Especially with ruling pens and railroad pens. I hit a point where I had the clients requesting that their jobs be scribed (engraved). I could do that faster. (didn't have to wait for the dang ink to dry) plus I then could use screens on the composite positives to really dress the package up.Even figured a way to add color to the mylar prints using the QuickProof dyes. Sold a bunch of them. Local firms really liked that.

Craig

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Scaling a plotted drawing??
« Reply #13 on: June 28, 2004, 02:14:52 PM »
Speaking of scaling, we once had a contractor call in telling us our Electrical Single/One Line Diagram was not to scale. It was off by 200' and we needed to correct the situation before he could continue. Needless to say, this contractor was booted off the project. Thats like asking someone how long the building is and he/she puts a plastic scale on the monitor to measure it.  :lol:  :lol:

CADaver

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Scaling a plotted drawing??
« Reply #14 on: June 28, 2004, 02:30:34 PM »
Quote from: Dent Cermak
Contact prints were so much easier than the ink on mylar. Especially with ruling pens and railroad pens. I hit a point where I had the clients requesting that their jobs be scribed (engraved). I could do that faster. (didn't have to wait for the dang ink to dry) plus I then could use screens on the composite positives to really dress the package up.Even figured a way to add color to the mylar prints using the QuickProof dyes. Sold a bunch of them. Local firms really liked that.
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