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Export to pdf yields wrong dimensions

Mats_Knutsson
Advisor
Hi,
It's small but however I don't understand where the "clutter" comes from.
/Mats
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.
1 ACCEPTED SOLUTION

Solution
Minh Nguyen
Graphisoft Moderator
Graphisoft Moderator
Dear All,

Thank you very much for your opinions about this issue!

I looked into our system and Mats's question was answered by our colleague. Here is our developer's explanation:

1. The standard error tolerance in Archicad is 0,01mm, which seems absolutely tolerable in a building. Most of our codes don't work more precisely than this.

2. If you print to a virtual PDF printer, the difference will be larger. In the print workflow precision is less important than drawing the whole requested area, including the lines on the edge. For this reason, we use a pixel-size rounding down in the page size, so in the worst case, the page content will be smaller a little bit. The size of the difference is the same as one or two pixel's size. Therefore the proportion of the difference depends on the resolution and the page size as well, but generally is 0.1-0.2%. On a printed paper the one pixel difference on a whole page is totally unrecognizable. However if you print to a virtual printer and then measure the size, you can find it.

If you want to bring the PDF back to Archicad and 0.1-0.2% difference is not acceptable, we recommend directly save the layout/view as PDF or use Publisher function instead of a virtual printer.

I hope this explains the situation. Please let me know if you have any questions!

Best regards,
Minh

Minh Nguyen
Technical Support Engineer
GRAPHISOFT

View solution in original post

12 REPLIES 12

Barry Kelly
Moderator
Is it because of the round end to lines in Archicad?


Barry.

One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10

Mats_Knutsson
Advisor
Barry wrote:
Is it because of the round end to lines in Archicad?


Barry.
I sincerely hope not. I've sent it to our local rep support.
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.

Anonymous
Not applicable
Mats,
PDF exported for Archicad is typically more accurate than that exported from Autodesk products, whenever I check a PDF in Bluebeam from Archicad they dimension correctly but from either AutoCAD or Revit there is a small discrepancy (up to about 1mm / meter)

Scott

Mats_Knutsson
Advisor
sboydturner wrote:
Mats,
PDF exported for Archicad is typically more accurate than that exported from Autodesk products, whenever I check a PDF in Bluebeam from Archicad they dimension correctly but from either AutoCAD or Revit there is a small discrepancy (up to about 1mm / meter)

Scott
Good but doesn't help me 😉
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.

Isn't this the result of scaling something to a papersize (assuming you are measuring something on a PDF with other software)?

Somewhere in the magic of DPI, PDF file format etc etc something gets lost?

Something like IFC or DWG should yield better result for 3rd parties checking dimension etc
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nl

ArchiCAD 9-24 NED FULL
Windows 10 Pro
Adobe Design Premium CS5

Mats_Knutsson
Advisor
Erwin wrote:
Isn't this the result of scaling something to a papersize (assuming you are measuring something on a PDF with other software)?

Somewhere in the magic of DPI, PDF file format etc etc something gets lost?

Something like IFC or DWG should yield better result for 3rd parties checking dimension etc
yes pdf...which is what we use more and more. Clever programs should have the ability round numbers. Just curious where this comes from . No answer from GS support yet.
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.

For what it's worth: I notice the same issues when exploding a vector PDF in Archicad: the dimensions are no longer 100% accurate. I assume it has to do with changing things from a 1:1 scale to a 'grid' of 300 dpi (or whatever setting your PDF uses) on the page size.

I'm not sure if there is much that can be done about it on the Archicad side of things.
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nl

ArchiCAD 9-24 NED FULL
Windows 10 Pro
Adobe Design Premium CS5

DGSketcher
Rockstar
As Erwin said there is a translation to PDF compromise. I frequently have to work from vector PDFs and rely where possible on the displayed dimensions. In my experience you cannot rely on the PDF vectors which will always have potential errors. If you want to share reliable 2D data save the view to DWG, (until GS sort out reading PMK files in different versions of AC. ).
Apple iMac macOS Monterey / AC25UKI (most recent builds)

Mats_Knutsson
Advisor
DGSketcher wrote:
As Erwin said there is a translation to PDF compromise. I frequently have to work from vector PDFs and rely where possible on the displayed dimensions. In my experience you cannot rely on the PDF vectors which will always have potential errors. If you want to share reliable 2D data save the view to DWG, (until GS sort out reading PMK files in different versions of AC. ).
It's more a general question concerning all users of pdf's. Have to live with it I guess. The use of pdf's in digital apps is booming while we print much less. Mega-pdf + Dalux/Streambim/similar is the way to go..."paperless" projects.
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.

DGSketcher
Rockstar
You have a valid question Mats, fully supported by the "paperless" argument. What accuracy should we expect from PDF? However, there is that fundamental disclaimer that tends to appear on most drawings "Do Not Scale from these Drawings" and "Always work from figured dimensions. I believe the same is relevant to digital documents. As suggested above the likes of Bluebeam may give accurate feedback from vector drawings but the disclaimers should still apply, particularly if the publisher is less than perfect with their drawing workflow.
Apple iMac macOS Monterey / AC25UKI (most recent builds)

I would argue that PDF is the 'wrong' file format for checking dimensions etc, while I still recognise that a lot of software out there went this route.

Personally I always ask for DWG and/or IFC from third parties to do any clashing / checking of dimensions, as I do not trust the inaccuracies of the PDF format.

I do like PDF as a format of how are things supposed to look, since it handles fonts fine. DWG are also a pain in the ... to print without pensets etc and really a relic of the dark ages in this regard!
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nl

ArchiCAD 9-24 NED FULL
Windows 10 Pro
Adobe Design Premium CS5

Solution
Minh Nguyen
Graphisoft Moderator
Graphisoft Moderator
Dear All,

Thank you very much for your opinions about this issue!

I looked into our system and Mats's question was answered by our colleague. Here is our developer's explanation:

1. The standard error tolerance in Archicad is 0,01mm, which seems absolutely tolerable in a building. Most of our codes don't work more precisely than this.

2. If you print to a virtual PDF printer, the difference will be larger. In the print workflow precision is less important than drawing the whole requested area, including the lines on the edge. For this reason, we use a pixel-size rounding down in the page size, so in the worst case, the page content will be smaller a little bit. The size of the difference is the same as one or two pixel's size. Therefore the proportion of the difference depends on the resolution and the page size as well, but generally is 0.1-0.2%. On a printed paper the one pixel difference on a whole page is totally unrecognizable. However if you print to a virtual printer and then measure the size, you can find it.

If you want to bring the PDF back to Archicad and 0.1-0.2% difference is not acceptable, we recommend directly save the layout/view as PDF or use Publisher function instead of a virtual printer.

I hope this explains the situation. Please let me know if you have any questions!

Best regards,
Minh

Minh Nguyen
Technical Support Engineer
GRAPHISOFT

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