I opened a ticket on the Altium support line and the response I got was:
"Thanks for your support request.
I had an internal conversation about the document. It is not possible to import KiCad into Altium designer (or Circuit Maker)."
Which is kinda sad, seeing that Altium is trying to get KiCad users to switch tools:
https://www.altium.com/solution/kicad-library and
https://www.altium.com/solution/kicad-pcb-design-software-free-download.Regarding the PCB panelizer, I need to have control over the fiducials and the frame, since it's going to be assembled off site, so I really need the PCBs on Altium.
I've spend the entire morning generating gerbers and then importing the gerbers in Altium and converting them to PCB, but the results aren't perfect. Sometimes you lose a pad, sometimes it's a bit of ground plane... Right now I'm trying to export from KiCad to Eagle and then import the Eagle files to Altium, see if that works... but since Altium is so vocal about getting people to change tools, it should have an importer at least.