Creating a multi-board layout

I’m looking at building something which consists of two PCBs connected by flat flex cable. Within a Kicad project, is there a good way to do this, or should I create two separate projects?

If the boards are going to go out as two separate sets of design files, I would personally have two projects. That just makes it simpler. If you document the flex cable connections properly, that should help.

The downside of two designs (two projects) is that you can have only one open at a time. Unless there is some trick I don’t know about.

I’ve done that before. The schematic consists of both the circuits, with the 2 connectors where the flex cable connects having “similar” sounding net names (like +5V_PCB1 and +5V_PCB2). This way, the nets don’t get connected, but you can still figure out which goes where. I also position the flex connectors aligned and next to each other on the schematic so it’s easier to figure out, with suitable explanatory text in-between. When the net list gets imported in to PCBnew, you end up with 2 bunches of components (PCB1 and PCB2) which are not interconnected.

Hope the explanation makes sense.

On Windows I just open a new Kicad instance.