I had develop a ngspice.lib for symbol, and parrallel with ngspice.cir file to expose addition spice model…
I hope it help you as it help me… This should work for all KiCad version from 4.0 to 5.0.
You need to add spice directive to include the ngpsice.cir file in your schematic.
ngspice.cir (1.6 KB)
ngspice.lib (10.7 KB)