I've got a large set of terrain tiles that I can successfully add to a prefab and use that to build an AssetBundle, but when I call SetNeighbors() on the Terrains it doesn't seem to take effect. Manually adding a script to each terrain object to call SetNeighbors() works, but that's a major pain. Is it possible to store the neighbor associations in an AssetBundle and/or a prefab? My Pro trial is up in five days and I'm still deciding whether to purchase (in other words, I'll give anyone who responds before then an automatic upvote).

New to both Unity and C#. Here's what I'm trying, minus the fat:

In a loop over tile heightmaps:

TerrainData terr_data = new TerrainData();
terr_data.SetHeights(0, 0, heightmap_tile);
GameObject terr_tile = Terrain.CreateTerrainGameObject(terr_data);

Then, when the loop is finished:

SetTerrainNeighbors(...); // Calls SetNeighbors on the Terrain component of each terr_tile GameObject. I suspect this code is fine, but I can drill down if folks want.
EditorUtility.ReplacePrefab(terr_parent_GameObject, terrain_prefab, ReplacePrefabOptions.ConnectToPrefab);
UnityEngine.Object[] terr_prefabs = AssetDatabase.LoadAllAssetsAtPath(terrain_prefab_path);
BuildAssetBundleOptions bundle_opts = BuildAssetBundleOptions.CollectDependencies | BuildAssetBundleOptions.CompleteAssets;
BuildPipeline.BuildAssetBundle(null, terr_prefabs, "Assets/"+prefix+"_bundle.unity3d", bundle_opts);

Suggestions?