DWG to PDF Hatch Problem

[SeaRR85]

I'm using AutoCAD LT 2007. I'm using solid hatching in my DWG drawing. When I convert from DWG to PDF, the hatching on the PDF seems to have some mysterious gray lines running through it. Please help! I don't like gray lines!

[hellnback]

Try changing the rotation of the soild hatch... (I just made that up so don't know if it'll work)

but also try printing to the PDF at a higher resolution.

[lstarbird]

I'm using AutoCAD LT 2007. I'm using solid hatching in my DWG drawing. When I convert from DWG to PDF, the hatching on the PDF seems to have some mysterious gray lines running through it. Please help! I don't like gray lines!

 

I'm having the same issue. Did you ever find a resolution?

[SeaRR85]

Nope, never found a solution. I have AutoCAD 2012 LT now and it still has the same issue! I've tried using a couple different PDF printers (Acrobat, Bluebeam) both exhibit the same issue. I did eliminate the issue once using the default "DWG to PDF.pc3" file but using this is not acceptable for my needs.

[lstarbird]

I finally found the fix yesterday! It actually is only a preview issue in Acrobat and/or Reader. While in Acrobat/Reader, if you go to Edit > Preferences > Page Display and uncheck “smooth line art”, the preview shows up better! With or without this selected, if you print a hard copy of the PDF, the lines don’t appear!

[JosephSpence]

Yes, it is a preview issue in Adobe Reader

[Daniel P.]

For anyone still experiencing this issue, I have a solution after years of it plaguing me.  While it may be an Adobe reader setting that causes the PDF to display this way, it's still an obnoxious problem, because it also impacts other Adobe programs, such as Photoshop or Premiere if you import a transparent PDF and then convert to a transparent PNG, etc.

 

Now, this isn't really a "fix" for whatever is making AutoCAD cause the problem, but it does solve it on the back end.

 

1. Copy your solid hatch three times (you'll have four total).

2. Right click on each of the other three solid hatches and change their rotation angle, so that you now have four solids, each at 0, 45, 90 and 135.

3. Move all hatches back on top of one another.  PDF will now plot without the streaks.

 

I tried this with two hatches, one at 0 and one at 90, and it seemed to work until I converted to PNG and tried using the image in a Premiere project.  The streaks were better, but they still showed up again just barely over bright backgrounds.  But having the four hatches on top of one another totally got rid of the issue.  It's annoying to have to do, but whatever.  It fixes the problem.  Hope this helps someone.

Edited December 14, 2020 by Daniel P.

[f700es]

Interesting solution but how does this affect the PDF file size?

[Daniel P.]

1 hour ago, f700es said:

Interesting solution but how does this affect the PDF file size?

You know, to be honest, I didn’t make note of that because I was only using PDF as a stepping stone to a transparent PNG in this case.  Interesting question.

[f700es]

So what are you editing the PDF in, software wise? I used to bring in CAD PDFs into Adobe Illustrator but now I just do the fills in Illustrator and just skip the Acad hatches all together

[ammobake]

I've often wondered about this and it's an interesting observation.

An interesting side note - and something you can try at home - Take a drawing with solid hatch.

Print the hatched object DWG to PDF, take that PDF and down convert back to DWG in Autocad 2021.

 

You will notice that one hatched area is treated very strangely.

 

If you convert the PDF back to DWG and insert it as block, go into the block editor.

You will notice something that looks similar to this.....

 

 

I'm assuming what is going on here is Autocad is scanning the PDF as it converts - breaking down the vector graphics and linework into objects recognizable by Autocad in the most efficient manner it sees fit.

 

In the case of a hatch (example being the block above) it converted this one to 68 triangular "SOLIDS".  So it must have considered 68 triangle solids the most efficient use of processing power when producing the conversion.

 

Furthermore, they show up as a grey color (like color 252 or something).   But the layer is white and they print as solid black.  So that's possibly just the visual style stuff coming into play I dunno.  But it's interesting.

 

Thought I would share lol.

 

Kind of a neat, handy little trick for someone wanting to convert a bunch of hatches into solids perhaps.  But that's a pretty niche kind of application.

 

-ChriS

[ammobake]

My own advice for your specific issue is not to use a solid hatch and print it as black unless absolutely necessary.

Personally, the only solid hatches I include in my final prints are one of 3 colors - 251, 252 or 253 (shades of grey).  But in my case the only reason I sometimes use grey solid hatches is to provide additional context or highlight something specific to make it pop in the final print.

 

IMO, it is more pleasing to the eye, uses less toner, and allows you to achieve the same result of making something specific "pop",  if you will.

 

Using solid hatches as shades of grey Is a trick I learned back in '04 and it can make for a really nice looking drawing - which is like half the battle.

 

-ChriS

Edited January 8, 2021 by ammobake

[Dana W]

^^^THIS!