Viewing drills in Gerber


I am trying to view a set of gerber files.
The drill files don’t show up. I read they have to be in Excellon format, whatever it is,
but I think it may be a simple extension problem. All the files I have are:

  • .phd format: display well
  • .drd format : don’t display at all.
    There are also a few minor issues, for instance unexpected characters, but it apparently doesn’t
    prevent to work fine.
    The .drd files look like GCode, which G90 being an absolute move command, tool commands
    (T01, for instance), which are what it says, tool selection. T01 is tool nb 1. And M30 command
    at the end, which makes sense.
    Does anyone know how to display drill in Kicad’s Gerber viewer?

I assume this set of Gerber files was made with some other program. Correct?

When you open drill files in KiCad’s Gerber viewer, you can disable the file extension filter in the lower right corner to show “All Files”. This is what it looks like on Linux with XFCE desktop (The window itself is just platform specific).

If you’re never going back to the original generator you could also rename.drd with .drl extension. (IIRC, not at computer now).


Thanks for your replies.

I tried, it doesn’t work.
You can notice on the right theat the layers 15 and 16 are drd files, but you can also notice that
in all the circles, there should be vias.

I also tried that, but in this case, gerber view complains about unknown commands.


drd is a drill description file, it defines the drill size and is supposed to be viewed by the operator(you) to set the drill machine, then the accompanying drl file which only defines the drill location can be loaded.
You can also merge the drd and drl file by hand editing. Just open some modern drill file with your favorite text editor to get some feel. It is just CNC GM code.


Thanks for your reply.

You can also merge the drd and drl file by hand editing. Just open some modern drill file with your favorite text editor to get some feel. It is just CNC GM code.


In the meantime, I opened a relatively recent set of gerber files, generated with Kicad a year ago
or so, using Kicad 6.
The problem persists and the drills are not shown.
So maybe I should have started here: is it possible to display the drills in GerbView? If yes, how?

NB: I have produced this circuit, and it has drills.


Screenshot from 2023-02-03 12-13-18

Yes, you have to load in the drill files, not just the Gerbers.
Once you do, the holes are shown on a separate layer.



Thanks for your reply. Maybe I wasn’t clear enough, but I did load the drill files. You can see in the
image above that layers 15 and 16 are drd files. Beside this, I also changed the extension to drl,
which does not chang anything. Beside this, the 2nd clipping comes from a project made recently,
and I got the boards produced. And they are perfectly normal which means that the drill files are
right. The files don’t even show in the right pane, which means they weren’t loaded.


Try turning off the visibility of all the layers except the drill files and see if you can see the ‘holes’.
I have had it in the past where they are hidden under the other layers.

1 Like

I opened a Gerber and drill file set made with KiCad, and the drills show as an layer with circles just as in the screenshot posted by 3Dogs. But for KiCad it’s all graphics and it just draws circles. It is not like in the PCB editor where drills are drawn as black holes, and you only see the circles if the drill file is selected and it is drawn on top of all other layers.

Thanks for your replies.
In the meantime, I opened a newer board, and now I can see the drills. Now what I’m doing
is a PHP converter. I just mimick the files I got displayed, and try to recreate similar files with
the .drd files. Right now I got the correct output format.
I’m not too sure about the scaling. Here is a part of the stdio I get from the PHP script.

→ X277.622Y303.2125
→ X380.746Y303.2125
→ X362.839Y307.467
→ X259.715Y307.467
→ X156.591Y307.467
→ X53.467Y307.467

The value after → is what the drl file should look like, and I guess it will do the job.
The scale factor for the time being: multiply the integer number by 0.0254
It still looks a bit too big.

By the way, one issue with gerbview: if I select all the gerber files of a project, it opens
them all except the drl file that I have to open separately by a specific menu command
like open drl files. I’m sure it wouldn’t be that difficult to change the code so that the
dri files are loaded automatically when selected.


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