I do not know if Jmonkey can generate triangles base on a group of points. I searched the Doc but have not found. So I wrote a Delaunay triangulation package myself. This package can create triangle mesh form random Vector3D points. I think it will be useful when we dealing with the terrance.
It is unfinished, I just put the image up here. If you can not see the image you can visit my blog
http://double1984.jimdo.com/网站首页-homepage/delaunay/