Is it possible to combine terrain and static meshes

I am thinking along the lines of having overhangs and caves in the world. I know this is not possible with terrain from heightmaps, but i wonder if you can somehow swap out some of the mashes in a terrainquad with static meshes you create manualy.
That way it would be possible to use a heightmap for the terrain and on certain areas of the terrain you switch out the terrain mesh with the static one for cave entrances or overhangs.
I am just not sure how to start trying out to swap out meshes of the terrain quad, or if trying to do this is futile from the start.

Another question would be if you can use the terrainquad/terraingrid to create a world made entirely out of static meshes.
Asking this because i was thinking about going full static but on a larger scale world this would mean a lot of verticles in all those meshes, so it would only be neccesary to load and display those that the camera realy sees, wich essentialy is exactly what terraingrid does. Can this be used in such a way or would i have to bake my own system to load/unload static meshes split up in chunks so i don’t have to load the entire world in one go.

I’d take a look at some of the voxel terrain stuff and see if that is helpful for you.

Even the box world stuff handles a lot of what you need although you would need to de-box it.

I tried to work with the terraingrid allready, but it seems you can’t make it not create a quad.
Wanted to create a world with given boundaries, so it would not be needed to load the neighbour even if camera is close to the edge (edge was a high cliff wall anyways so not even for viewing), but terraingrid was creating a plain quad as a minimum whatever i did.

Is there something that is able to load scenes on demand ? Might go the way to split up the world in chunks and design those as scenes (jo3 files), but then still need the mechanic to load the next chunk once it would come (or a bit before it might) into view of the camera.

Will take a look at box world. From what i know about the mechanic of those worlds this might provide a good deal of those functions ?

Actually you can cheat here,

just have your level at like 100m height, and have the quads you not need at minimum height, that way in the valley created you can stuff your own static mesh.

Pagination is the keyword for splitting the scene up. The answer is that it’s been discussed a lot and there are a few implementations around on the forums but nothing “complete”.

Empires suggestion is good for a workaround - but I’d still look at box worlds and/or voxel terrain.

http://hub.jmonkeyengine.org/forum/topic/terrain-side-project-video-updated-with-3-adventure-videos/

This is a workarround to switch out the meshes if needed or prevent something from being drawn (and jm3 makes sure it is not send to the grafic card to be rendered if out of view) but it is still a waste of memory wich i try to avoid everywhere, even if it is only a small ammount. In this case this could very well become quite a large ammount i imagine.