High Voltage Footprints with PCB Cutouts

I have a couple of surface mount high voltage parts that require a cutout in the PCB below them. I have found two methods to deal with this, since the footprint editor won’t allow drawing on Edge.Cuts:

  1. Draw the cutout on Eco1.User (or something valid), save, then manually edit the .kicad_mod file to change the Eco1.User lines to Edge.Cuts

  2. Draw the cutout on Eco1.User (or something valid) with a note, and draw over it in pcbnew in the Edge.Cuts layer after it’s placed.

Method 1 makes future editing tricky, and the part 3D view weird, but works. Method 2 means I have to manually edit in pcbnew everytime I place the part and keep track of Edge.Cuts when I move the footprint around (and make sure I don’t forget it!).

Is there any better method to do this?

Method 1 in footprint 3D viewer (note it assumes the board edge is where the new cutout is):

Both ways, pcbnew:

3D Hidden, pcbnew (looks good!):

What version of kicad are you using? Your Method #1 is the best to use; you must also explicitly draw a board outline or else the software will assume that your cutout is the board edge. Cutouts must not touch the board edges or the behavior will be erratic.

I’m running kicad-r7308.03da56a-x86_64. I understand that the viewer interprets my cutout as the board edge, and therefore gives an inverted PCB view. However, adding a board edge in the footprint inverts the cutout in pcbnew, as there is an extra box in the Edge.Cuts layer.

I think currently Method 1 is the best bet, noting that the PCB in footprint 3D view will not be representative.

Will changes like this persist after the footprint is modified with the Footprint Editor, or will it be necessary to run the footprint through a text editor after every time you save the footprint from Footprint Editor? (Or, in the worst case, will Footprint Editor identify the invalid layer the next time you load the footprint and remove the Edge.Cuts data entirely?)


Ah, ok - this is a bug with the previewer then.

In the build I’m running the change did persist after file editing. I was even able to adjust the Edge.Cuts lines and OpenGL mode and re-save. However, if you hit ‘E’ to edit the lines, you get this warning:

Then this dailog:

Hit Cancel and everything stays as-is, but hitting Ok may force them to a new layer based on the layer drop-down.

Ah, ok - this is a bug with the previewer then.

Is this a bug, or expected behavior? I half expected it, since I had two board edges in the footprint. Is there a way to define a board edge for the preview that is not based on Edge.Cuts?

Edge Cuts on footprint are not expected or even allowed, so the 3d viewer doesn’t consider that configuration in footprint editor…
to manage edge Cuts in footprint you have to tweak kicad editing the footprint in a text editor…
May be that can be improved, but still is not a bug because you are asking for a not standard allowed behavior/configuration
That would be in a whishlist

Edge Cuts on footprint are not expected or even allowed, so the 3d viewer doesn’t consider that configuration in footprint editor…

I agree. Logically part of me feels, as a rule, cutouts should always be managed in during layout in pcbnew, since it is a mechanical modification of the board. On the other hand, putting the cutout in the footprint in this case I feel may lead to less errors.

Thanks guys.

Footprints that include cut-outs are unusual, but certainly not rare. For example, one recent thread, Reverse mount LED cutout , featured reverse-mount LED’s. A few components that interface with the power distribution mains require a cutout to satisfy insulation or creep-distance requirements. Some components, which are more thoroughly described as “modules”, require cutouts for various reasons.

It would be convenient to create Edge Cuts directly in the footprint editor, even if it means dealing with a squawk asking, “What you’re trying to do is a little unusual. Do you REALLY mean it?”


It would be convenient to create Edge Cuts directly in the footprint editor

@dchisholm so you are asking for adding a feature…
Then a whishlist not a bug

This is a bug; it should be possible to modify the viewer so that it does the right thing when previewing a footprint. Components which require cutouts should be handled correctly. The footprint editor might not allow users to draw on Edge.Cuts, but that is really a limitation of the editor.

this condition cannot be tested because it is not allowed by the editor… so imo it is not a bug, but a feature request…
anyway I consider this also useful (I do similar tricks often); thus removing this limitation of the editor would be appreciated

1 Like

This is available with StepUp now:

Edge.Cuts for footprint allowed

1 Like

People that have never required cutouts in footprints and don’t see the need are lacking in imagination. I have to work on the packaging of my PCB’s as well as just spit a load of parts onto a PCB and tell the mechanical engineer “that is it” because I am the mechanical engineer as well.

Making products these days requires a lot of mechanical imagination. I am not designing a PCB version of something I hand wired with buttons and a screen. My screen and button height must be identical as this is also an IP rated unit so the button must be at the right height.

The solution is to put the screen PCB under the main PCB with the screen poking through the main PCB. This means a carefully routed cutout is required that I have no intention of creating over and over again so method 1 is attractive because it also makes the output model of the design work.

1 Like

whoa, it is being worked on? thank you! so if i use method “1” will this be an issue in the future releases that support this feature or will it just accept existing lines on the cutout layer and allow more to be created or edited? Basically what will compatibility look like do you think?