I am new to Minecraft and FTB. If I use my old saves from vanilla minecraft with FTB will new materials like uranium and tin ore be available for me to mine? Or do I need to start a new game to be able to mine the new materials?
Well, the new ores would not be in the overworld, or at least not in any of the generated areas, but you could always create a mystcraft age for the new ores and biomes and stuff. You could also create a new save and transport your old save in as a mystcraft age.
I have not explored much of the vanilla map, I just traveled a little ways from my original spawn and started building a massive biodome/Jetsons structure in the sky. So If I run really far can I find new the materials and biomes? I just want to keep the giant building I made as home base for now.
well, I'm not sure, haven't tried it myself. I would say, just try it, no harm in that. If it works, great, if not, oh well, at least you tried.
Yeah, if you run out far enough for new chunks of the world to be generated, there will be mod ores and blocks in the new chunks, it's always a way to fix things on Matta's server if he forgets to add copper and tin generation to the world on default, so we just run a fair distance away, and voila! new ores.
You will need to copy from your .minecraft/saves/"<Vanilla Minecraft World>" folder to your FTB "<ModPack>/minecraft/saves/" folder and then start FTB client and open the single-player world. If you are running a server, you will need to copy the "world" folder from your vanilla Mincraft server to the FTB "world" folder.
Note: If mystcraft is in the FTB pack you're using you can also just create a few mystcraft worlds to go get all the new ores.
Note that Thaumcraft world gen can be generated in already generated chunks, take a look in the TC3 config. This also does apply to aura nodes.
If your building is in the air you can use MCEdit to import it to the new world, they are some tutorials on youtube or upload your map and I'll do it for you
