Footprint has no errors in editor, but many when placed on PCB

Footprint has no errors in footprint editor, but many when placed on PCB footprint or referring me to a 3rd party footprint site.

I created a footprint with a round smd pad in the middle of a polygon.
Error check in editor shows no errors.
I placed the footprint on my PCB and get an error for the pad interfering with the polygon!
I, also, get an error for the trace to connect the pad to other parts on the PCB.

What do I need to do to get rid or errors?
I recently upgraded to Kicad 6.0.5.

Can you show, for example with a link to a datasheet, what you really wanted?

This doesn’t work, so what is your real goal, what did you want?

Indeed, a screenshot would be nice.

I’m guessing you want the polygon to be a part of the pad.
This can be done by:

  1. Select the pad.
  2. Right click and from the popup menu: Edit pad as Graphical Shapes [Ctrl + E]
  3. Draw the polygon.
  4. Press [Ctrl + E] again to exit the pad edit mode.
  5. You should probably delete the other polygon.

If this does not help, then post a screenshot, and also add the exact text of the errors you get, and what you expected.

paulvdh thanks. that’s a new command to me. I’ll try it!

You don’t get extra points for a fast response.
It’s better to first try it, and then respond whether it works or you have some trouble with it.

My original intent was to create a footprint for a custom sensor.
A circular area with 3 NPT holes. I needed clearance around these holes, editor ignored the 10 mil clearance I set for those holes.

Sorry for being quick, I retire in 5 days and I’ve got to get this done!
I tried ctrl+E and it let me expand the radius of my pad til it filled the area I needed.
But it also filled in around my 3 NPT holes in the sensor, so they have no clearance.
I need 10 mil clearance around those 3 NPT holes.
My manual way was to place a circle around each hole to define the clearance, then place one large circle to define the total sensor size, with a pad in the middle for electrical connection. This works to create a footprint of a large round pad with the 3 smaller NPT holes, and editor error check finds no errors.
But when the footprint is placed on the pcb, I get the errors.

It seems that the footprint editor isn’t checking for errors the same way the PCB layout is.

Polygons aren’t zones, they aren’t filled like PCB zones. They are just completely filled and don’t care about clearances.

I don’t know any reasonably easy way to do what you need, if I understood that correctly (you could still give a link to a datasheet or something like that).

Here’s the image.
One error for where the pad interferes with the polygon, and 2 for where the incoming trace crosses over the polygon and large perimeter circle.

Actually, if you open the footprint and pcb files in a text editor, they are very similar.
I’m thinking of editing the text file and putting a zone into my footprint to see what happens!

One part of the meaning of “Similar” is: “Not the same”.

Another approach is to just use a small pad, and then add a zone in the PCB.
There are no real arcs in zone boundaries though.

You can simulate a circle by:

  1. Draw something on a copper layer.
  2. Use the array function to create a circular array.
  3. Draw a polygon by snapping t the array points.
  4. Delete the circular array of objects.

Another, possibly quicker way:

  1. Use a wizard in the footprint editor to create a footprint with pads in a circle.
  2. Place that footprint on your PCB.
  3. Draw the zone by snapping to the pads.
  4. Delete the footprint.

Good attitude! Unfortunately it doesn’t work. You don’t even have to edit text files. You can draw a shape in the footprint editor and use context menu → Create from Selection → Zone. KiCad recognizes it. But you can’t attach a net to it and it can’t be filled, it will be empty when you have placed the footprint in the board.

The footprint checker could (and probably should) warn about the pad/polygon problem. But it can’t of course say anything about the track.

Do you want the whole circular copper area to be one pad? Then you should create a custom pad. I’m still not sure how your copper area is actually composed, but you could try a very simple thing: select the real pad there and in the context menu choose Edit Pad as Graphic Shapes (Ctrl + E). Then go back to the normal mode in the same way (Finish Pad Edit). All graphic items in the same layer which overlap with the pad either directly or indirectly will become part of the pad.

I created a fill zone from a circle in the pcb file. I copied that text from the pcb file to the footprint file. KICAD DIDN’T CRASH!
The footprint editor won’t let you place a fill zone, but if you copy one with a text editor, it knows how to edit it.
Unfortunately, Kicad doesn’t respect the fact that you have a fill zone in the footprint, so it doesn’t fill the zone!
I thought I could sneak this one past them, but alas not.

So far, I’ve tried everything you all have suggested, but no success.
I guess I’ll have to live with 3 errors for now til Kicad adds the fill feature to footprints.

Thanks eelik and paulvdh!

Today is my last full day at work, so I’ll have to think about this in my retirement!

Did you try to create a custom pad, as explained in my previous post? Do you need one copper pad of that round shape with holes in it?

I, too, noticed that a zone in a footprint doesn’t crash KiCad automatically, it may have been something else, or the zone combined with some certain action.

You can turn the errors off in the DRC dialog. Go to the error message and use the context menu.

I don’t think filling would ever be added to footprints. Filling is a dynamic action, the purpose of the zone is to react to all items on the board. Footprints need fixed shapes, and dynamic shapes can be added to the board. If you need a complex copper area which can be attached to a net, you need a custom pad. Being able to use a fill and then convert the filled shape to a polygon would be fine, but the need for very complex shapes which can’t easily be done with normal graphic shapes is rare.

You can attach the footprint file here, and we can see how it would be done properly. And please give a link to the datasheet of the sensor!

I tried all suggestions and none was any better than my first try.
The difference between fill zones and polygons/custom pads is that fill zones respect a pads clearance values and polygons/custom pads ignore and fill everywhere.
My 3 NPT holes need a clearance of 10mils.
I don’t like turning off any error checking since at some point those will be real errors I want to catch.
The fact that the footprint editor does not catch the “pad in a polygon” error sound like a discrepancy that needs to be addressed.
My biggest complaint about Kicad was that symbol editor, schematic editor, footprint editor, and pcb editor all have different rules and commands. 6.0 got a lot better. I’ve used many cad packages and Kicad is still very good! hopefully in the future I can contribute more to the effort.
Thanks, Tom

But you seem to have the shape you want, it just gives DRC errors. And if I’m correct, it’s possible to create a custom pad out of it which doesn’t give errors. You probably just don’t know yet how to do it correctly. That’s why I asked for the footprint file, so that I could see how you made it, and how it could be fixed.

The sensor is a custom design I have patented.
It can detect very low pressures measured in mm of water column, but still handle 20 PSI without breaking.

I will have to study up more on creating a custom pad.
Right now I have to clean out my office before my retirement party.
I will get back to this later though!

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