View original (French)

Transparent Areas of the PDF

CARON -  
Z-eFiT Posted messages 70 Status Member -
Hello,

My PDF is externally referenced in my DWG and, as usual, Autocad makes the white areas of the PDF transparent (these areas are indeed white when I open the PDF with Adobe, as evidenced by the checkered background that does not appear in those areas). I'm looking for a solution so that this PDF reference does not have transparent areas in my DWG. Let's avoid easy answers like "put a white background" or "insert an OLE." My only question is: on a blank DWG, I insert a PDF, what can I do to ensure that the white areas remain white and do not become transparent?
Help!

Configuration: Windows 7 / Mozilla 11.0

17 answers

  1.
    contrariness Posted messages 17905 Registration date   Status Member Last intervention   6 244
     
    You need to check how the white zone is defined... because it can be on a different plane when imported or even be declared as non-printable, and in that case, what is below comes above.

    In a PDF, the background (paper) is transparent by default if it is a vector file integrated into another vector file. For the background to be opaque, it must be a color declared with a name (like opaque white for example), or it must be given a color in a color space (RGB or CMYK).
    1
  2. CARON
     

    So how can I change the background so it's not transparent but solid white? (I'm not very familiar with Adobe)

    0
  3. CARON
     
    Furthermore, I realized that it is when I attach the PDF to my DWG that the white areas become transparent. I imagine that what I am looking for is a function in Autocad that would force the white areas of the PDF to remain white and not disappear.
    0
  4. Z-eFiT Posted messages 70 Status Member 20
     
    Hello,
    In fact, when a PDF comes from a scanned file, the background is white because it doesn’t differentiate; for it, it's just an image.
    Did you use Xrefs to attach it?
    What version of AutoCAD do you have?
    0
  6. CARON
     
    Hello,

    This PDF was created using the QGIS software (so it is not scanned), the white areas of this PDF are either part of a table background, an IGN background, or even text backgrounds. So apart from the print margins which have no background, everything else has a white background. The white areas of the PDF are definitely white (I verified this by enabling the checkerboard for transparency). To insert my PDF in Autocad, I use the XREF (it's like using _PDFATTACH). And that's where the whites become transparent (I applied a green Solid hatch to see this). If I print this PDF from Autocad, the holes appear (in green). I also noticed that Autocad always prints with a transparent background.

    I am using Autocad Maps 2013 and 2014.

    I have a lot of PDFs to print from Autocad, I really need them to no longer have these holes where the whites are.

    If you don't fully understand what I'm saying, do a test, take a PDF, a text for example, and attach it in Autocad, then create a colored Solid hatch.
    0
  7. Z-eFiT Posted messages 70 Status Member 20
     
    It seems to me that what you're doing is not possible. There is indeed a transparency parameter, but it affects the entire PDF. I think the only way, as you mentioned in your first post, is to put a white background behind it. :s
    0
  8. CARON
     
    I'm always stuck; holes appear in the printout with a fine cyan outline. The only way to prevent this from ruining the drawing would be to force the PDF to remain opaque when importing into AutoCAD. Does anyone have any ideas, please?
    0
  9. Z-eFiT Posted messages 70 Status Member 20
     
    Could you send me your PDF via private message so I can take a look? (if it's not too confidential of course)

    --
    CAD Designer, 3DS Max, Cinema 4D, ALLPlan, Photoshop
    0
  10. CARON
     
    I am sure that if you try to attach a PDF as an external reference in AutoCAD, whether it's mine or any other, the problem will be the same. In AutoCAD, place a solid hatch (green for example) underneath your PDF and you'll see.
    0
  11. Yoda
     
    Hello,

    I tried with a cadastral extract in PDF from cadastre.gouv.fr
    The object hook works in edge mode, for example, so it is indeed vector-based.
    I placed a light yellow hatch under the PDF (managing the display order, PDF on top) and when I print, the cadastral extract is printed in black on a yellow background.
    So it should work for you too.

    Give it a try by managing the display order.

    Talk soon!
    0
  12. CARON
     
    What I'm trying to achieve is not just having another color fill the gaps, but ensuring there are no gaps in the PDF. Even putting a white background doesn't interest me. AutoCAD should not decide to replace the white areas with transparent ones but should leave them white.

    The reason I'm imposing this constraint is that we can see a cyan outline around all these transparent areas when printed, which makes the drawing look awful.

    I can send, to anyone who gives me their email address, a copy of a PDF before AutoCAD and the same PDF after AutoCAD. Everything will finally be clear.
    0
  13. Yoda
     
    You can upload the files on http://www.cjoint.com/, note the generated link, and post it here.
    0
  14. CARON
     
    Here are the PDFs I was talking about earlier:

    Before: http://www.cjoint.com/?3CdoreOqZEt
    After: http://www.cjoint.com/?3CdotJBkkvI
    0
    1. Yoda
       
      I observe in the drawing that after one box has disappeared, the other appears faded.
      Is that what was meant to be seen?
      0
    2. Yoda
       
      Sorry, I didn't see correctly. In the drawing, there is a new box, and the box with the scale appears faded. Is that right?
      0
    3. CARON
       
      On the PDF from AutoCAD, only the table and the location map have been added in AutoCAD; in fact, we can see that they are the only elements that do not suffer from the color bug, but they are JPEGs, so it is normal that AutoCAD does not process them.
      0
  15. contrariness Posted messages 17905 Registration date   Status Member Last intervention   6 244
     
    Is it significant pixelation (generally blue) that you can observe in your PDFs (after) that you are referring to when you say that it is no longer a white background?
    0
    1. CARON
       
      Yes, it's because AutoCAD creates holes that these hole outlines appear. That's why I'm desperately trying to prevent AutoCAD from making these holes.
      0
    2. contrariness Posted messages 17905 Registration date   Status Member Last intervention   6 244
       
      I don't know what you use to create your PDFs, but try reducing the compression rate (not the resolution, the compression)...

      Or prohibit JPG compression in favor of ZIP compression in your PDF.
      0
    3. CARON
       
      I create my PDFs using QGIS, a free software. I would have liked to redo all my plans in JPEG to ensure that AutoCAD does not cut off the white areas, but it would take me at least a week to redo everything (for those interested, all my composer templates are quite heavy, which significantly slows down the software). In order for my plans to export to PDF, I had to lower the resolution of several of them, and some are not even in raster format. The compression is already low. If you look at the first PDF, it is of fairly good quality. The whole problem comes from AutoCAD.
      0
    4. contrariness Posted messages 17905 Registration date   Status Member Last intervention   6 244
       
      We should verify more carefully, but I remain convinced that you have a compression issue (based on the PDF files you attached, which may not be original files?).

      In any case, for these examples, the objects contained are images. You have a compression rate of 98%, which is excellent for small file sizes but disastrous for quality.
      Moreover, between your first PDF and the second, you are "over-compressing" with the same rate. Automatically, you introduce additional degradation...
      Upon verification with Pitstop, your images are compressed to 3.04% of their original size!)

      On the other hand, I don't understand how from Autocad, which is a drawing software, you manage to obtain an image in PDF... logically, you would expect vector objects... (although Autocad is not known for producing high-quality PDFs when using textures... but still).
      0
    5. CARON
       
      Okay, the quality is poor, but it wouldn't show if AutoCAD didn't make holes.
      0
  16. Yoda
     
    Hello,

    Have you tried converting one of your PDFs to JPG to see if the result is better?

    See you!
    0
    1. CARON
       
      The result would definitely be better, but given the heaviness of my software, it would take me at least a week to redo everything in JPEG. Plus, the quality is not the issue. If the holes in the PDF remained filled, my problem would be solved.
      0
    2. Yoda
       
      What you call "holes" are, in my opinion, pixels altered by the insertion of the PDF into AutoCAD, possibly because the image resolution in PDF format is too low.
      That's why it would be interesting to see if the result differs with a JPG file rather than a PDF; at least you would know for sure.
      There's no need to redo everything. You can open a PDF with Adobe Acrobat Pro and save it as a JPG. You can also use PDF-XChange Viewer (which is free); it has an export function to JPG.

      There is also a possibility that AutoCAD is fading the attached file. In that case, it's simpler:
      you set the system variable XDWGFADECTL to 0.
      0
  17. CARON
     
    Well, I think I don't have a choice. For the next files, I will directly save them as JPEG before attaching them to AutoCAD. For those that are already in PDF, I will convert them to JPEG. It seems there is no solution to fill the gaps of the PDFs in AutoCAD.

    If anyone finds a solution, please suggest it, but it's unlikely.

    Thank you for looking into this with me.

    See you!
    0
  18. Z-eFiT Posted messages 70 Status Member 20
     
    Have you thought about the "CLEAN" function?

    --
    AutoCAD drafter for 10 years.
    0