topic Insert PDF: Scale wrong in AutoCAD Forum

Insert PDF: Scale wrong

rudhamstile — Sat, 30 Nov 2019 00:10:05 GMT

I know its heresy but I like inserting PDFs into Autocad; especially ones from Sketchup because I can do lovely elevations and combine them with my equally lovely Acad 2d linework. I don't care what you might think, (including SU users), my paying clients like them so thats fine and dandy with me. I'm glad I put that out there now.

However I would love to know why when I insert an A2 PDF into an A2 autocad drawing the scales are a distinct 25.4 times incorrect -which is obviously an imperial units anomaly. (Its similar in either PSpace (my preferred) and MSpace where one has to apply a further scale factor 25.4 then 50 times for example)

I've checked dwgunits and insunits for clues but found none.

Re: Insert PDF: Scale wrong

Alfred.NESWADBA — Sat, 30 Nov 2019 09:12:35 GMT

Hi,

I don't know why it is built that way.

However, I'm used to ignore the paper format, for me the only important size is the geometry inside the PDF.

So what I do:

using _PDFATTACH to get the pdf attached into the drawing
command _ALIGN or _SCALE (depending if I already have geometry in the drawing) to align/scale the pdf to correct position/scale.
at least I use _PDFIMPORT to convert the geometry from the pdf (only the one I need) to AutoCAD geometry.

HTH, - alfred -

Re: Insert PDF: Scale wrong

pendean — Sun, 01 Dec 2019 00:08:54 GMT

25.4 is a metric conversion unit: the problem is likely your PDF creation method most likely, we import scaled PDFs all day long (your rant aside) and we only scale by the imperial scale we created the PDF with.

Post a PDF of yours that has this problem in AutoCAD, lets all try your file.

Re: Insert PDF: Scale wrong

rudhamstile — Sun, 01 Dec 2019 23:17:14 GMT

Thanks for the reply and suggestion. The method you describe is generally how I normally would import too, but for me there's the hassle of having to scale from known geometries, which for me just never seems right. By creating images to a scale on a regular sized sheet in SU and then importing that to a similar sheet in Acad removes that guesswork.

Its not a problem now I know there's an exact 25.4 ratio difference - its just annoying that somethings not right somewhere.

Ive checked SU Layout for their page /export settings (since its so simple with hardly any variables), and Im pretty sure everything is fine there too.

Re: Insert PDF: Scale wrong

rudhamstile — Sun, 01 Dec 2019 23:47:25 GMT

Thanks for your input.

The Sketchup Layout page settings/ export variables were my first port of call; thinking there was an obvious user error, but it seems all is fine there - The settings are an amazingly simple affair offering few clues. I will ask SU for their opinion. Its not a major issue, just an annoyance that something is awry.

Re: Insert PDF: Scale wrong

Alfred.NESWADBA — Mon, 02 Dec 2019 07:50:22 GMT

Hi,

>> By creating images to a scale on a regular sized sheet in SU and

>> then importing that to a similar sheet in Acad removes that guesswork.

Please, do not (never) use PDF as data exchange format for CAD data. It's limited accuracy results in geometry objects that do not have the same size as they had in the original CAD system. PDF does not hold geometry in double precision, so you lose some digits and get objects with different size back.

SketchUp can read and write dwg-/dxf-files (>>>source of information<<<), so I strongly suggest to use that interface.

From what I have tried now it does not depend which parameters you used to create the PDF, AutoCAD seems always to measure the paper format inside the PDF as Inch and that value is then used for importing (if anyone else has a different experience, please let us know that). For now, if you want to have that better/differently handled you can send your input to the product by that site: >>>AutoCAD product feedback<<<

- alfred -