I found another handy bit of simple old-school Windows freeware, Height Map to OBJ. Note that it needs a square height-map, not an oblong one, or it will give “out of memory” errors.
It does smoothing as it exports to a mesh, effectively removing the unwanted “terraces” which can be so difficult to remove from the greyscale heightmap itself. At the cost of smushing away fine details. But these could potentially be added back with software which can add erosion and other “re-detailing” to an OBJ terrain.
The resulting OBJ loads into Poser fine and fast at 20%, and then needs a 700% scale-up on the Y axis. Once in Poser it’s quite biddable. Here a 10-mile wide white terrain is being ‘textured’ purely by four lights in the Poser OpenGL viewport, with Comic Book mode providing the ink lines. On its own it won’t impress, but it would provide a good starting point for a hand-drawn tourist map, etc.
So far as I know there’s no Vue-like “show different texture types at different height elevations” material for Poser, aka a ‘distribution shader’. Possibly with Poser 12 such a thing will be enabled? Or could a script build such a thing on the fly, by inspecting the mesh?
With far more of a learning-curve, TerreSculptor is now wholly free and will also import a height map and export an OBJ mesh. The OBJ is far less biddable, though.