This lampshade is derived from the Fischer-Koch C(Y) triply periodic minimal surface.
See here for video: https://youtu.be/MzilEqBCLFE
See here for stable download: https://thangs.com/mythangs/file/57441
The outer diameter is just under 120mm, the inner diameter is approximately 75mm. Two heights are provided of approximately 200mm and 155mm.
Ensure that you use a low-temperature light source with ample room between the light source and lampshade.
Printing with a .4mm nozzle is recommended.