Rocket lampshade

I needed a replacement lampshade for a sconce in my son's bedroom. After a year of seeing nothing, I decided to make one. I wanted to print the Sketchup Stock Wallace Rocket but I had too much trouble trying to make a printable shell so I drew my own version.

First attempt, it broke loose from the platform on build so I added some thickness to the fin bases and bottom of the top. Unfortunately this messed with the fit and I had to dremel off the flange from the top and print a ring to go betw