3rd Person Free Roam...Where to Start?

i've started one myself, very the same as the previous answer, i built a terrain, made the mountains, added lakes, a town, and others, a train constantly going around the map, bridges ect, a logical place according to the story to start and a place to restart when you die (like gta starts at the hospital ect) add your character (obvs) and add people or animals and i fild "fog" is great with large freeroam maps also (edit, render settings) it makes it all look a lot better, it also helps with a big terrain, ins$$anonymous$$d of adding more together (incase u don't know cus it took me a while to notice u can go terrain, set resolution)

One thing to put in $$anonymous$$d is the amount of draw calls...this is how many times the engine has to render specific items. First of all, us low poly modelling for ALL your assets..and then try to re-use a specific item a number of times (maybe changing the texture now and then)...so if you are using instances of lets say a building, it would be much more smooth playing than adding a large variety of buildings. another thing is to use Occlusion culling and lightmaps...this reduces cpu and gpu usage tremendeously...problem is, i had to learn this the hard way....

best of luck