This is a 38-sided die as is talked about in Gravity Falls. A polyhedron with 38 faces is called a snub cube, so this model was made originally on GrabCAD
I added in the numbers. This die isn't fair (some faces are square, and some are triangles), but it's just a cool thing to have for fans of Gravity Falls.
When I printed it, I used Cura to slice it:
Layer Height: .15mm
Print Speed: 20 mm/s
Travel Speed: 60 mm/s
Build Plate Adhesion: 6mm brim
I also let Cura generate support to make sure it would be able to handle the faces on the bottom side of the print.
Because the original model was not mine, I actually just scaled it down in Cura to 45%, which made the whole die a little over an inch across. After printing it, I realized I probably should have oriented it differently on the build plate. When mine printed, the number 36 was the bottom face. This is a very difficult number to clean out with such small text. I recommend orienting it with the 1 as the bottom face.
I still consider myself fairly new to 3D printing,
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Put the 1 as the bottom face!