I'm currently working on a game (obviously) and I've decided I'd like to expand the terrain. The options I have are adding another terrain plane, or making the one I'm using much larger. However, Either one comes with its challenges. If i make a new terrain plane, I have to try to match up the mountains and edges of the terrain which can prove to be a major pain. If i enlarge the size of my current terrain, obviously everything else in the scene shifts from its desired location and the texture mapping needs to be adjusted to scale.
My question is, is there an easier way to do this task, or would it just be simpler to start the terrain over now and make it huge before I get too far. And if that's the case, what's a nice huge size terrain to work with for a large scale game (kinda sandbox traveling around, lots to explore. etc.
There's an editor script available that matches terrains up seamlessly. The only thing extra you have to do with multiple terrains is use Terrain.SetNeighbors on them so the LOD matches up, so that way would be easier right now. It may be easier in the long run to have a single terrain to begin with, depending on how you want to set up your world. On the other hand, with multiple terrains, you can always expand as needed without having to redo anything.
Basically, it lets you "import" the heightmaps from 4 terrain tiles (a 2x2 grid) into one larger terrain - so you can fix the seams between them using Unity's built-in terrain sculpting tools. Then when you've fixed the seams, you can "export" the heightmaps back to their individual tiles.
Be warned though, there is no "undo" functionality in this version, so experiment with it a bit first. I will be releasing another version next month with automated edge-blending functions, etc. too.
Ive thought about to the same thing. A solution Ive considered implementing (sorry, no definitive answers from me today) was to place the second terrain some distance away and create a tool that would programatically create a terrain that (linearly?) extrapolates between the differences.
I know its possible but I havent delved deep enough into terrain to be able to do it at just this moment. Please keep us/me advised of how you solve this problem.