Poor PDF Display Quality - Export from AutoCAD

[hupjack]

My goal is to efficiently publish my multi sheet drawings from AutoCAD to a single PDF file for e-submittal to my clients who do not have AutoCAD and would prefer to open a PDF on their device of choice.

The file must look like it will print when viewed on the client’s screen with any PDF viewer (web or desktop) and it should have enough resolution to print to paper at 11x17 without any loss in quality.

The problem I’m having is with my appendix pages at the end of my output document.

The appendix is made from equipment data sheets (PDF format files attached within AutoCAD) and framed by my title block, and certain PDFs are displaying poorly on the screen. (Some of them display poorly but print fine, but this is not an acceptable deliverable to my client).

The Source PDF for the last page from the manufacturer looks perfectly good: http://unirac.com/wp-content/uploads/bsk-pdf-manager/6_SM-2703-CERTIFICATION_6.pdf

If you zoom in you can clearly see this is a raster image, but there must be something not-so-good happening for the results to look so bad when the source is perfectly readable.

Calling attention to the last page where the problem lies:

Here is a screen capture of the last page of this file viewed via Google Drive’s PDF viewer: http://screencast.com/t/VeMOFeNNYjB

This file was printed to PDF using the publish command from AutoCAD 2015 LT on my mac running the latest OS: El Capitan 10.11.4

https://files.acrobat.com/a/preview/9cd47e59-ded0-470a-adac-6aed8cc10338

This file was printed to PDF using the publish command from AutoCAD 2014 on my Windows 10 PC

https://files.acrobat.com/a/preview/c2ad141b-e1bc-4c18-a52a-fbe09537df38

This file is 1/5th the size of the one produced by my mac but the last page still displays equally bad.

To summarize:

Issue 1) 5x larger PDF export from Mac version of AutoCAD

Issue 2) Terribly screen display of certain PDFs when raster PDF sources are attached in AutoCAD file.

I won't pretend to know if this is a bug with AutoDesk or Adobe's product, so I've reported the problem to both companies.

Adobe: Let me know if there is anything more I can provide to help you troubleshoot and solve this problem.

[Dov Isaacs · Accepted solution]

I downloaded and opened up the files you pointed to.

Observations.

(1) None of the issues here are associated with any Adobe products. The PDF files were not created with any Acrobat component.

(2) The file created from AutoCAD on MacOS is entirely color raster imagery at 600dpi using ZIP compression, In contrast, the file created from AutoCAD under Windows uses text and vector where possible with the raster images compressed with lossy JPEG. That explains the dramatic difference in size (and ironically quality - the smaller file is higher quality)!

(3)  The pages from http://unirac.com/wp-content/uploads/bsk-pdf-manager/6_SM-2703-CERTIFICATION_6.pdf are in fact JPEG2000 compressed images at 150dpi with no text and no vector. Although Adobe's desktop and mobile PDF software has no problems with JPEG2000 raster images, various third party viewers are not so robust. The artifacts that you see via  http://screencast.com/t/VeMOFeNNYjB are likely due to a crufty JPEG2000 implementation. High quality JPEG or ZIP (Flate) compression would have eliminated this particular issue!

          - Dov

[hupjack]

Thanks Dov for looking into this!

I couldn't have told you what it was that AutoCAD for Mac did differently than the AutoCAD for PC, but it looks like you were able to uncover what AutoDesk did by looking at the PDF results.

I know AutoCAD for Mac is much newer software, and maybe they did "quick and dirty" and "lower quality" implementation of printing to PDF. Sounds like that is the case.

The source PDF from Unirac at 150 dpi sounds like it leaves much to be desired, but AutoDesk certainly made it look much worse.