Space Colonies?
Are there any guides out there to creating new planet types? Including changing the planet visually as well? I would like to create a new planet type which actually isan't a planet at all, but a space colony. An O'Neill Cylinder to be exact. It would act exactly the same as a planet; is colonizable, has tactical and logistical slots, has nearby resource asteroids, and has it's own grav well. It would just visually be different. Is this possible? Any guides?