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The first thing I did was load gerbers that have known shorts. I loaded the IPC netlist and do not get any errors. Also the IPC layer is blank. Am I doing something wrong ?

I want to confirm the following:

1    You're able to load your Gerber files correctly.

2    You're able to load the IPC Netlist File (after import is complete should see a message stating how many nets were loaded) - You can also press F2 after the Netlist import to see a log stating how many nets were imported.

3    If the nets do not align with the Gerbers than you can view the following:

4    Extract your CAM Nets (from the Gerber).  Go to menu:  Tools / Nets / Netlist extraction... (accept the defaults).

5    Run Netlist Compare and you should get any differences.

Netlist compare is one of the most common uses for FAB 3000, and we have many examples in the support forum with movies showing how this can be done and how to deal with any problems:

Thanks again, and I look forward to hearing from you.

Best regards,


hanks for sending the sample IPC file.  I am able to import the Nets fine.

Note:  By default maybe you are not able to view the test points (when zoomed out), so you can adjust the FAB 3000 display to always show those small features (even when zoomed far away):

Note: I would recommend that you import all netlist test points onto the same layer -- uncheck "Create Separate Layer(s) per side" during Netlist Import.  Some engineers like to have their test points placed on separate layers - but I think when starting out it's better to have everything on the same layer.

Next once you can confirm the Netlist has imported fine, you'll need to tun on all layers and view if the netlist file is aligned over the Gerbers -- for whatever reason many PCB Layout software will export the Netlist (and sometimes NC Drill files) with a different coordinate system than the Gerbers.  If that's the case, you just need to align the net list layers so they are correctly over the Gerbers.  Once that's done you're ready to check for any potential netlist errors.

Note: Before running Netlist extraction Does you Gerber design contains Blind/buried drills?

Here's a blog I wrote last year about using Netlist comparison to verify your design integrity:

Thanks again, and please let me know your progress.


That works fine if you start by just loading that file. If you have gerbers already loaded it does not load anything on the ipc layer.

Thanks for the quick response.  The existing Gerbers should not matter.  After importing both the Gerber and IPC netlist file and you're unable to view the Netlist Test points -- it would either be the Netlist is not aligned with the Gerbers (and offset somewhere relative to the Gerbers) or hidden underneath the Gerber pads.

If hidden underneath the Gerber pads, you can turn Fill Off - Go to menu:  View / Fill / Outline; and you should see the circular test points under the pads.  You can also use the Translucent option to create the see-through appearance when Fill is on - menu: View / Translucent

If the IPC Netlist File is not aligned with the Gerbers, than our support link should help explain how to align them:

Here's a quick tutorial showing me load Gerbers and then load the IPC Netlist file (in FAB 3000) - plus use the Translucent and Fill options I have described above.  

Note:  I recommend using the command AutoLoad, because it will import all the Gerbers, Drills, and Netlist files simultaneously -- go to menu: File / Import / AutoLoad... and select the folder which contains all your Gerber, Drill, Netlist files.  FAB 3000 can also load everything in a zip file: menu: File / Import / Compressed File...

Best regards,


Ok it looks like it depends on the zoom level you are at if the test points display or not. My gerbers at not aligned with the  test points. Shouldn’t the netlist compare produce errors ?

Glad to hear you were able to view the netlist test points.  If the netlist is not aligned FAB 3000 really can't produce any errors unless you check the Netlist compare options "" "".  To truly find any shorts or opens, you've got to have the Netlist Test points aligned with the Gerbers.  It's 2017 and I'm not sure why some PCB Layout software still export their Netlist with different coordinates from the Gerbers..  In any case you simply need to use the "Align Layers" command in FAB 3000.  Select a Pad in the Gerbers (usually like a lower-left) and then select the lower-left Test Point (the entire Test point layer will be moved to align over your Gerbers - use the reference points you have chosen).  The Support tutorial should better demonstrate this.

Once you've got everything aligned, extract your netlist and run Netlist Comparison to verify any differences.  You can try the Test example we included with FAB 3000 - called "Net_Check" (located in the FAB 3000 examples folder .../Examples/Net_Check).  If you can run that sample set of Gerbers and find the differences, you should be comfortable enough to try it with your own Gerbers.  Previously I sent a support link which shows a movie demonstrating Net Comparison on that "Net_Check" example.

Thanks again, and please let me know how it goes.


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