I'm planning a game right now, to be made in Unity, and I'm trying to decide how I'll approach the basic level construction. Essentially, my game takes place on an island in an infinite ocean, very similar to Wuhu Island:
My question concerns all the stuff heightmaps can't handle. To use Wuhu Island as an example, note the lighthouse cliff, and the nearby similarly jutting-out cliff. The volcano itself is also empty, and there are some tunnels through it on the other side.
I was thinking I would just model the entire island myself in Cinema 4D, but as I read more about the terrain system, it seems Unity has special optimized rendering systems in place for terrain objects. Would I be shooting myself in the foot performance-wise if I just built my island entirely by hand? This will be for mobile, so the little stuff might well count. Am I even approaching this question correctly - if not, how would you best go about creating (something very close to) Wuhu Island as a level in Unity? Is there any reason for me to not do it as one mesh? I have effectively zero experience with 3D game dev - only rendered 3D video/stills for other applications, so this is a learning process.