procedural

I am aware you can edit the generic background to make a custom greenscreen or whatever you like, but where are the procedural backgrounds stored? I want to replace some of the textures with nice Hubble images or similar.

I posted this in the wrong-ish place so I'm re-submitting it here. Note: I found all these pictures on google, sorry :l I've looked at a small number of voxel-based games, and I'd list this one near the top (a tie between two actually) of my list for potential beyond what people could ever...

So... this is a big one. I've looked at a small number of voxel-based games, and I'd list this one near the top (a tie between two actually) of my list for potential beyond what people could ever dream of ever experiencing... but none of them (so far) have ever seemed to consider the...