Mapping Art Layers to PCB Layers

This is the magic in PCB art - taking a vector drawing and converting it into a circuit board. To make this happen, this guide uses Gingerbread by Winterbloom. 

To achieve this, the image layer names are chosen to match the PCB "sandwich" shown below. On each side of the PCB, there is the silkscreen, solder mask, copper, and unchangeable substrate.

The layer names are on the left in the image and correspond to the layers shown at right.

A Very Important Note on How Layers are Specified

For the Front and Back silkscreen layers -- F.SilkS and B.SilkS -- and for the Front and Back copper layers -- F.Cu and B.Cu -- material will appear in KiCad wherever you draw a shape in the design.

For example, if you draw a Copper Circle, that is where the copper will appear in the copper layer.

If you draw a shape on a silkscreen layer, the silkscreen color will be deposited. It may be up to the board manufacturer if silkscreen can be printed on copper without a solder mask between. If you can, it might be best to specify silkscreen below areas you want to have silkscreen.

KiCad and Gingerbread treat the Front Mask F.Mask and Back Mask B.Mask as inverted! Where there are items in these layers, the solder mask will NOT be present. The preview in Gingerbread will show the mask layers as they would appear on the printed board.

Edge Cuts and Drills are special also. The Edge.Cuts layer specifies the outline of the circuit board. This could be simple, like the nearly square floppy earrings on the Overview Page. Or the design may be more complex like the weasel above. For interior edge cuts, see the FAQ below.

The Drills layer is very special also: Gingerbread walks through all of the shapes in that layer and converts only circles into corresponding non-plated, through hole drills in KiCAD. It is very easy to draw an ellipse instead of a perfect circle. Don't! Gingerbread will ignore non-round shapes in the Drills layer.

So, if your Gingerbread Drills layer does not show a hole, it is not that another layer has "covered it up" - likely the object is not circular.

Debugging Image Layer to PCB Layer FAQ

Q: I drew circles in the Drills layer but they don't show up in Gingerbread.

A: Check they are indeed circles and not ellipses - the horizontal and vertical dimensions of a circle must be exactly the same. A physical drill can technically only drill round holes (end mills are used for slots).

Q: On a Mask layer, the material is where I don't want it and not where I specified.

A: The F.Mask and B.Mask layers are special. You must draw where you DON'T want mask material.

Q: Besides outside Edge cuts, can there be interior cuts?

A: Circular drill holes are the most common. But yes, some PCB manufacturers allow for cuts within the PCB outer perimeter. Be sure your manufacturer can handle such cuts. The gear below on the Winterbloom Gingerbread page has four interior cuts.