I'm talking about mods like toxic worlds. That mod seems awesome, but there are a few questions I want answered: 1 - After installing such a mod, where and how do the new worlds spawn? Do they replace existing planets OR do they create new solar systems with the modded planets in place. 2 - Let's say I have the mod installed and there are some toxic worlds out there. If I hosted a server and played with some friends that DON't have the mod installed, how will they see the worlds? Will they see them as they have to in the nav console, will they be able to go to them with/without me OR will they not be able to see them at all AND won't be able to go to them?
1. It depends on the mod, and the coding, assuming the person who made such a mod would make it as functional as that. There would definitely have to be some coding involved in this type of a mod, so it can depend on it. The person can either replace worlds, or possibly create new, but that most likely would be later when the full modding API is released. 2. Well, the server doesn't check the packets, so if you're hosting the server, it's loading the mods from your folder. I'm not sure if they'd see them at all, and if so, what would happen. I do remember though, that, I was messing with the silverore.item file a few days ago. I had updated it, restarted the server and logged back on. I had put a comma on the last argument (IE; "fuelAmount" : 50, }) so the file was basically corrupt. When I mined silver ore it'd come out as a green block (perfectly generic material or something) and my friend could see it as well, and pick it up. That may or may not answer your question for #2, but I can't really provide a straight forward answer as there'd be too many "ifs" or qualifying factors for parts of your question. The short answer would probably be that your friends would be able to see the world, but for it's full functionality, they'd also have to have the mod, especially if you wanted the same worlds/coordinates.
Generally speaking, yes, unless the mods have been released and you really wanna play them. To be safe, I'd recommend everyone who's going to be playing with you to obtain the mod and then you can see how it works/if it works out OK.