I'm making a recreation of a star map from another game. But to do so, I require a few new planet types.

Such as Ice Asteroid Fields, Ice Clouds, Smog Clouds, Green Nebula's, Space Stations, enz.

I would love to make these myself, but how to do it? The Ice fields are easy, just retexture the asteroid fields. Ice Clouds cant be too hard either, just use a Plasma Storm and make it icy particles, just with other nebula's. But the Space Station requires a new model, which is kinda hard.

I have no idea where to start working on new planet types. I've seen mods with new planet types, so I know its possible.

But where to start?