Differing Hole Notations In Eagle CAD?

Question

I was just creating some vias in Eagle and was playing with the drill diameter, and for some reason Eagle seems to put differing notations around the hole when the size changes, is there any reason for this, or is it purely cosmetic?

For example, here's a crosshair looking thing

And, when I decrease the drill size just a bit, it changes to a concentric circle with a diagonal line:

Furthering my confusion, some differing stuff happens when creating regular holes with the drill tool, here is a crosshair at 45 degrees:

I also got the concentric circle with a diagonal line, but also this weird fish-looking thing?

Is there any sense to be made of this? Or is it just something eagle does when the pad/hole size changes so that the marking is clear that it's a hole?

Thanks!

(this is eagle 7.6.0 if that matters)

Answer 1

As specified in the EAGLE manual on page 292, this is intentional. EAGLE uses 19 different drill symbols. The 18 symbols shown below are used for drills of a specified diameter. You can specify which symbol to use for which drill size in the Layout Editor under Options -> Set -> Drill.

(image from EAGLE manual)

Finally, the symbol Ø is used for drill sizes, which were not specified in the settings.

This allows you to easily recognize the different drill sizes. An additional drill legend can be generated with the ULP script drill­legend.ulp.