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Exploded AutoCAD Import Vs. Exploded PDF Import From Same File (AC24 &AC25)

ka
Contributor

Greetings!

 

I am realizing, now with a second project, that when importing a survey CAD file and PDF export of the same file, the lines/vectors are not aligned/correct.

 

I assume the CAD is "more correct"/accurate, since it is imported at full scale, but I am not sure. Thus, I assume there is some "translation error" when converting the PDF vectors into Archicad lines? I have tried to rotate, scale, move the files and they don't align, which in turn, distorts the linework. See attached screenshots below.

@Barry Kelly @DGSketcher @Rex Maximilian @Laszlo Nagy  

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Solution
DGSketcher
Champion

A survey CAD file e.g. DWG is a vector format with potentially high precision to fractions of a millimetre if necessary. PDF is a document format that provides accuracy based on the resolution of the printing grid. If you print full size it will appear visually accurate, but underneath the "vectors" will have been adjusted to suit the print resolution. This will mean when you import a 1:500 site PDF and then superimpose it on the source DWG file a larger scale e.g. 1:100 you will see divergence. In short, if you have a readable DWG use it. A PDF with dimensions may be sufficient for tracing, but I would never rely on its accuracy. If you do use it, then ensure all critical dimensions are checked.  

Apple iMac macOS Monterey / AC26UKI (most recent builds)

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Solution
DGSketcher
Champion

A survey CAD file e.g. DWG is a vector format with potentially high precision to fractions of a millimetre if necessary. PDF is a document format that provides accuracy based on the resolution of the printing grid. If you print full size it will appear visually accurate, but underneath the "vectors" will have been adjusted to suit the print resolution. This will mean when you import a 1:500 site PDF and then superimpose it on the source DWG file a larger scale e.g. 1:100 you will see divergence. In short, if you have a readable DWG use it. A PDF with dimensions may be sufficient for tracing, but I would never rely on its accuracy. If you do use it, then ensure all critical dimensions are checked.  

Apple iMac macOS Monterey / AC26UKI (most recent builds)

I'm no pdf expert. The printing resolution is true if such a pdf would be published via original software into a raster (image) based pdf. But the pdf format supports real vectors as well and this way shouldn't give you such results - based on your screenshots I believe you have a vector based pdf. It does depend on the original software from which the pdf is being published. Some do support better options but one needs to dig deeper into pdf publishing settings, like explained here.

I don't know how this offset is possible, to be honest. Probably a software export or import translation flaw, but I wonder on which side.

I always use vector based land survey data, mostly dwg and additional xyz from which I can generate the terrain model. If those two don't match I know that something is wrong (it happens).

Archicad 4.55 - 25 | HP Z840 | 2× E5-2643 v4 | 64 GB RAM | Nvidia Quadro M5000 @ Windows 10 Pro x64

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