Folks,
In order to solve a problem in our game development, I was able to produce these python scripts that are simple and can help you take the Mesh-based terrain from a program like Google Sketchup ( or other 3D mesh modeling app that saves .OBJ ) and convert to the TerrainBlock array structure that JME uses.
http://github.com/taboca/3D-OBJ-to-JME-TerrainBlock-converter-
Enjoy,
//arcio
BonecoDeNeve Games
Why do you want to do that? You could simply use a TriMesh, a TerrainBlock is also just that. What extra functions of the Terrain do you need?
Trimesh doesn't have getHeight and getSurfaceNormal for terrain following though or am i missing something.
getHeight and most important with terrainpage you can break the heightmap into several terrainblocks which have their own bounding volumes.