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printing to scale


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Just tried an experiment.  

 

1.  Draw a rectangle 50' by 24' on a design layer set to 1/8"=1' scale.

2.  Print from design layer (or sheet layer w/ viewport)

 

Result: printed rectangle is 50'6" by 24'7".

 

1.  Same rectangle on designer layer

2. Print > PDF > Open in Preview

3. Print (from Preview)

 

Result:  printed rectangle is scaled correctly.

 

MacPro > HP OfficeJet Pro 7740

 

What is going on?

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42 minutes ago, Kevin Allen said:

Printing from PDF os best practice. Most printers/drivers understand WHAT DF. They do not necessarily understand vwx. or other programs. 

Do you think if I brought in a stack of printers from different manufacturers that I would get different results for each mfr driver?

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I just tried it on my Canon MX920.

 

VW Design Layer, 1/8" scale, 24 x 50' rectangle center at zero, zero.

 

Printed from VW onto Letter and  Letter Borderless

Printer from VW directly to PDF Open in Preview and then printed from there.

 

All three prints were "identical" as close as I could tell by holding them up to the light.

 

But all three were slightly oversize when measured compared to the expected size. The 24' side was about 1.5mm oversize. The 50' side was about 2.5mm over the expected size.

 

I don't know what that means. I am relatively certain that I had all print scaling turned off. I am also relatively certain that I have printed and had output be exactly what was expected before.  

 

And even when I turn my time dilation meter to 30 minutes into the future I still get the same physical print.

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Hate to say it guys.  Printers have never been accurate.  Ok, sometimes they are, but that is usually dumb luck.  Kevin seems to be saying that he does well with PDFs, but if one needs accuracy, one needs to check the print out.

Using Truss tapes and the TM-T20II and with others using the TM-T20III we have found that accuracy varies with different papers, and different instances of the same printer.  We solve this by creating a 1:1 scale viewport of the tape to be printed.  The truss tape has a ruler on it and sample prints are made.  The scale of the viewport is adjusted away from 1:1 to fine tune the result.  With the cheap 3" Amazon paper, we have found a viewport scale of 0.989 usually works well, but that setting cannot be counted on between printers.  We have found that once a printer setting is found, it holds from session to session.

Michael's scale error seems larger than what we usually deal with, but I have heard of large scale adjustments.  They work, but are usually the result of some strange configuration of the drawing or printer.  Still Michael's scale difference seems large.  Michael, you should try printing to a viewport and find out what the scale adjustment is needed to get more accuracy.

HTH.

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1 minute ago, Mark Aceto said:

Printing from anywhere other than a PDF exported / published from sheet layer may as well be deprecated. It's about as useful as the vestigial arms on a T-Rex.

 

That's a bit severe.  Printing truss tapes described above works best from the sheet layer containing the viewport.  I have also seen PDFs print off scale by the same small amounts.  My experience seems to show it is the computer/printer interface that is the main issue.  One might get better results with PDFs, but all print outs need to be checked for accuracy depending on your tolerance for deviation.  That is why dimensions are placed on the drawing.  Dimensions should be placed on all construction documents in all disciplines.

My 2¢

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13 minutes ago, Mark Aceto said:
15 minutes ago, Sam Jones said:

Printing truss tapes described above works best from the sheet layer containing the viewport.


That's interesting, and would make a great meeting topic

 

In that particular case there is a lot to the difference between sheet layer and PDF.  Mainly, my users find it very difficult to make the page description work.  PDFs put another layer between the user and the printer.  AP Truss Tapes create 12in X 3in pages on the sheet layer, and allocate enough pages to be as long as the truss, plus some extra for end labels and markers.  The viewport is then centered on the page.  The Epson printer drivers allow for the creation of a 12in X 3in pages.  When this is done by a PDF and then sent to the printer there seems to be a hiccup between the PDF printer page description and the printer driver page description.  I haven't investigated deeply.  I just tell people to print from the sheet layer.

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17 minutes ago, Kevin Allen said:

One aspect which has not come up is the difference that I would expect between a laser printer, a cheap inkjet and a plotter.

Interesting?  Yes.  Who's got the time and all 3 printers.  Actually, I know a guy, but he doesn't have the time.  ...or care.  He's been sending everyone PDFs and carrying E size plotter prints to the job.  If he's not slaving away on the next corporate gig, he's walking his dogs, grilling, or working on the next item on the honey do list.

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  • Vectorworks, Inc Employee

So, let me understand. You're looking for accuracy of 1/8"=1' down to the difference of an unsharpened pencil?

Kidding aside, I just printed these on my HP Laser Jet Pro M477 and they are both spot on.
Directly from VW.
Top in a viewport and the bottom printed directly from the design layer.

Snag_986827b.png

 

I also checked via exporting to a PDF and printing. Same result. All are spot on.

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This reminds of an incident that happened to me many years ago.   I was trying to help someone out over the phone with a problem they were having with AutoCAD.
He was complaining that he was drawing a rectangle 2"x2" and that no matter how many times he drew it it was the wrong size.   After some back and forth I finally figured out his problem.   He was drawing a 2"x2" rectangle then using his ruler to measure the rectangle on the computer screen.

 

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