This has all files needed.
You will see that the 4 parts that make the extension mount together with M3 screws (M3x10 and M3x20) and M3 brass inserts.
The bottom collar holds the base and provides 4 anchor points for springs (NEEDED, since the VKB NXT EVO can not hole this extension unaided).
Infill: 50%
Supports: no need.
Raft: no need.
Perimeter walls: 4
SPRINGS ARE NEEDED - VKB NXT EVO CANT HOLD THE GRIP 400 MM AWAY FROM THE BASE.
ALSO, YOU WILL NEED TO EXTEND YOUR GRIP WIRES.
The author remixed this model.