topic Re: Export to pdf yields wrong dimensions in Documentation

Export to pdf yields wrong dimensions

Mats_Knutsson — Fri, 19 May 2023 20:06:02 GMT

Hi,
It's small but however I don't understand where the "clutter" comes from.
/Mats

Re: Export to pdf yields wrong dimensions

Barry Kelly — Tue, 13 Apr 2021 08:26:33 GMT

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

Barry.

Re: Export to pdf yields wrong dimensions

Mats_Knutsson — Tue, 13 Apr 2021 11:30:07 GMT

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.

Re: Export to pdf yields wrong dimensions

Anonymous — Wed, 14 Apr 2021 11:30:07 GMT

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

Re: Export to pdf yields wrong dimensions

Mats_Knutsson — Wed, 14 Apr 2021 13:49:58 GMT

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 😉

Re: Export to pdf yields wrong dimensions

Erwin Edel — Thu, 15 Apr 2021 09:04:24 GMT

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

Re: Export to pdf yields wrong dimensions

Mats_Knutsson — Thu, 15 Apr 2021 19:29:37 GMT

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.

Re: Export to pdf yields wrong dimensions

Erwin Edel — Mon, 19 Apr 2021 08:47:56 GMT

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.

Re: Export to pdf yields wrong dimensions

DGSketcher — Mon, 19 Apr 2021 21:37:12 GMT

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. ).

Re: Export to pdf yields wrong dimensions

Mats_Knutsson — Tue, 20 Apr 2021 07:49:47 GMT

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.

Re: Export to pdf yields wrong dimensions

DGSketcher — Tue, 20 Apr 2021 08:40:22 GMT

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.

Re: Export to pdf yields wrong dimensions

Erwin Edel — Tue, 20 Apr 2021 09:25:55 GMT

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!

Re: Export to pdf yields wrong dimensions

Minh Nguyen — Tue, 20 Apr 2021 12:49:31 GMT

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