Altium embedded boards
How to quote altium embedded boards on circuithub
Altium allows you to create a .PcbDoc file which references multiple child .PcbDoc designs - the embedded boards feature.
CircuitHub does not currently support the use of multi board designs in Altium. If you try to upload a .PcbDoc that contains multiple embedded .PcbDoc files the import will fail. The solution is to upload each of the unique designs separately.