I’ve created a terrain in 3DS Max. How do I save/export it so I can use it inside Unity as an actual
Terrain Asset ? I’m using Toms Terrain Tools and I have the AutoMagic feature, but how do I get it from MAX into Unity correctly ?
Also, Is a Heightmap just a black and white image where white is the elevation ? think I need a Splatmap ? What is that ?
Thanks, I’m new to Unity
The common method of getting landscapes into Unity is to use height maps. Models quickly become far too big and intense for the engine, particularly if you go for a high poly model. So most people just take the height map and import it, and deform a terrain object using the height map.
A splat map tells Unity where to draw rocks, grass, mud, whatever. It uses the different colour channels (RGBA) for different purposes. Where a splat map has red, it paints rock. Where is has green it paints grass. And so on.
You can make a heightmap of your terrain in 3ds max, there are several tutorials explaining what to do on uTube ( e.g. http://www.youtube.com/watch?v=V5QD6D9pYfE ) and use the heigtmap file in Unity.
However, there are some restrictions. First of all, to use the heightmap in Unity, it must have a specific resolution, therefore if you want to make a 1:1 copy from max to Unity it is going to be a bit more difficult. In addition, you won’t have the exact same terrain in detail. So if you need a terrain that fits to a specific mesh, for example a road, you won’t get happy. I suggest you to use T4M. It is fairly easy. Just export your terrain as fbx to Unity, open T4M and mark the mesh as terrain. You now have nearly the same options as in Unity, except the automatic billboarding. It is a lot more simple than messing around with heightmaps. Believe me, I spend a lot of hours on this topic when I was a beginner as well.
Good luck 
That youtube tutorial seemed a bit overkill, T4M looks quite cool but havent used it, but getting heightmaps from max isn’t too terribly hard if youre set on doing that, when i’ve done it i simply used a zdepth render element with an orthographic top down view. You can set your render to have a square aspect (use safe frames in your viewports to check it) and render at the resolution you wish, you can downscale/crop it in an image editor, the format for the heightmap can be tricky but photoshop can output the image in a raw image format unity can understand
But t4m might be a speedier more convenient option
I have been using Object2Terrain when converting my Google Sketchup Terrain models into Unity 3D terrain.
Ohh cheers, that looks ideal!