Actions
Forum Thread Details
  • Replies 4 replies
  • Subscribers 178 subscribers
  • Views 345 views
  • Users 0 members are here
Related

Streaky/split polygon ground plane

autodeskguest

Searching the newsgroup for an answer to this one didn't turn up any

matches (but I think I know a lot more about ground planes/polygons now!).

 

I have designed a double-sided board with ground planes on both sides

of the board.  When I print (as in File->print) the board with output

to a Postscript file, then view it (using evince - I'm running Ubuntu

by the way), I see both the top and bottom ground planes have small

horizontal slits in them.  A photo is worth 1000 words as they say.

 

Notice that the edge of the polygon is never affected, just the

inside.  Other signals (the regular looking traces in the image)

appear just fine as well.  The width of the polygon affects the

spacing of the streaking.  It's like there isn't any overlap of the

lines used to create the solid fill, and sometimes we see 'through'

between the lines.

 

I have also tried printing to a 'PDF printer' - a driver that acts

like a printer to the app, but redirects output to a file in PDF

format.  Using xpdf to view that file also shows the streaking effect.

 

This doesn't seem to affect the CAM files.  I have viewed those using

ViewMate without any streaking apparent.

 

All this has arisen because I wish to send a PDF of my layout to

someone for checking.  They don't run Eagle so I need some image

format that they can read.  I suspect I'll get a ribbing from them for

not running Protel; grr!

 

Any ideas how to stop this odd phenomenon would be appreciated.

 

Photo attached (hopefully).

 

-Martin

 

Attachments:
image
Parents

  • Robert Pearce wrote:

    On Thu, 8 May 2008 Eur van Andel wrote saying :

    You have a lot of layers turned on. If you display only the top layer,

    do you still see the slits?

     

    I don't think that has anything to do with it.

     

    Just out of curiosity, I tried printing just the top layer, and it

    exhibits the same problem.

     

    I suspect this is a graphics problem of your OS, not Eagle.

     

    No, it's not. I have the same issue when printing to a

    pseudo-post-script printer using Eagle 4.15 and with only one layer

    visible. It's a quirk of the way flood areas are encoded into

    post-script, I suspect, probably exacerbated by tiny variations in

    interpretation between CadSoft's test environment and ghostscript (since

    Martin is on Linux and my printer is hanging off a Linux server to get

    post-script capability).

     

    So what OS are you running Robert?  I thought about trying all this

    under Windows, but setting it all up was going to be some work (mainly

    due to security restrictions at my work).

     

    Changing to hatched and back makes no difference, but I think I found

    that setting the width/isolate/spacing differently helps.

     

    Indeed, changing to hatched and back doesn't help for me either, but I

    have also fiddled with the width/isolate/spacing settings without

    managing to remove the problem.  My understanding is that 'spacing'

    only affects hatched pour regions; trying different values here when

    using a solid pour didn't seem to change anything.  'Isolate' didn't

    help me either; it just results in more/less space between the pour

    and other tracks (as I believe it's intended).  'Width' does help a

    little, but I believe simply by the fact that by making it large,

    fewer lines are drawn to make up the solid pour thereby reducing the

    number of edges and hence spots for the background to 'leak through'.

      I didn't manage to find a setting that was acceptable.

     

    Fortunately this time I'm not using the print output for generating

    PCBs, but the CAM output instead.  In the past however, when making

    quick mock-up PCBs at home I did use the print output option (hack

    saw, UV box, bubble tank, drill press...), so it would be nice to

    solve this little puzzle.  I think when I used to make PCBs at home,

    they were always small and I didn't really know about ground planes

    and polygons back then, so never used them.

     

    Regards,

     

    -Martin

     

Reply

  • Robert Pearce wrote:

    On Thu, 8 May 2008 Eur van Andel wrote saying :

    You have a lot of layers turned on. If you display only the top layer,

    do you still see the slits?

     

    I don't think that has anything to do with it.

     

    Just out of curiosity, I tried printing just the top layer, and it

    exhibits the same problem.

     

    I suspect this is a graphics problem of your OS, not Eagle.

     

    No, it's not. I have the same issue when printing to a

    pseudo-post-script printer using Eagle 4.15 and with only one layer

    visible. It's a quirk of the way flood areas are encoded into

    post-script, I suspect, probably exacerbated by tiny variations in

    interpretation between CadSoft's test environment and ghostscript (since

    Martin is on Linux and my printer is hanging off a Linux server to get

    post-script capability).

     

    So what OS are you running Robert?  I thought about trying all this

    under Windows, but setting it all up was going to be some work (mainly

    due to security restrictions at my work).

     

    Changing to hatched and back makes no difference, but I think I found

    that setting the width/isolate/spacing differently helps.

     

    Indeed, changing to hatched and back doesn't help for me either, but I

    have also fiddled with the width/isolate/spacing settings without

    managing to remove the problem.  My understanding is that 'spacing'

    only affects hatched pour regions; trying different values here when

    using a solid pour didn't seem to change anything.  'Isolate' didn't

    help me either; it just results in more/less space between the pour

    and other tracks (as I believe it's intended).  'Width' does help a

    little, but I believe simply by the fact that by making it large,

    fewer lines are drawn to make up the solid pour thereby reducing the

    number of edges and hence spots for the background to 'leak through'.

      I didn't manage to find a setting that was acceptable.

     

    Fortunately this time I'm not using the print output for generating

    PCBs, but the CAM output instead.  In the past however, when making

    quick mock-up PCBs at home I did use the print output option (hack

    saw, UV box, bubble tank, drill press...), so it would be nice to

    solve this little puzzle.  I think when I used to make PCBs at home,

    they were always small and I didn't really know about ground planes

    and polygons back then, so never used them.

     

    Regards,

     

    -Martin

     

Children
No Data