Nobody else to create another shape other than sphere and cube in Space Engine for planets, moons, ... even if it's unrealistic but can serve for "asteroids" that are placed on planets to represent monuments for example.
Otherwise, here my Formyas system who collects all possible forms that can be done, but I have not managed to make the pyramid, if anyone can help, thank you for publishing it..
For now, it has the shape of star, a cube, a flat sphere and an "inverted" world (just a black bump map), a hourglass as well as the famous pyramid and a form unknow. I tried ringworld but don't work properly.
Thanks for help and share your forms here.
I would like disc but with   for the disc have atmosphere but spheric (like a dome view on the planet) :

test1