private Vector3 GetRandomSurfacePosition()
{
Vector3 randomPos;
Vector3 terrainDimension = SurfaceManager.SurfaceDimension();
do
{
randomPos = new Vector3(Random.Range(0, terrainDimension.x),
0, Random.Range(0, terrainDimension.z)) + SurfaceManager.SurfacePosition();
randomPos.y = SurfaceManager.GetSurfaceHeight(surface, randomPos);
} while (!CouldTreeSpawnIn(randomPos));
return(randomPos);
}