I have been getting more interested in using kicad’s 3d capability. Last year I was learning v6 but concentrating on building my symbol and footprint libraries – I did a few 3d renders of boards, but it was mostly for novelty.
This year with v7 I have been refining my libraries and filling in a bunch of missing 3d models, and I wanted to make a little board for testing 3d export. Instead of making a pcb to fit into an enclosure from hammond or new age, this time I wanted to make the enclosure to fit the pcb. A buddy has been teaching me 3d modeling, and this is my first design to come of the printer.
My test board is just a gizmo for adapting jtag/swd/tagconnect programming cables. The only design constraints I imposed was to use a single screw hole and to use rounded pcb corners for fitting in a filleted case. Kicad render:
I exported it from kicad as a step file, brought it into solidworks, and saved it as stl. Then, since I didn’t yet have a pcb from fab to proto with, I printed it so I can test fit it in my new case:
I took a few iterations to get an enclosure design I liked:
Bottom:
Top:
And then I could put my kicad “board” in for a test fit 
I want to make an assembly in solidworks to merge the kicad step file with the top and bottom case halves for a test fit. That would be the proper workflow before making anything, but I skipped ahead and just printed them out.