zedzeek:

I trust you are right so ill get on with it. Let me make sure i understood you correctly.

Do you suggest i go through each of those points every frame. Or only the visibility checking and rendering part? I could build the entire triangle-tree at load time and then traverse it to build the vertex array (still at load time). The terrain isnt dynamic so it wouldnt matter much when it comes to functionality.

personally if it was up to me ild skip the idea of doing a terrain with roam.
what i would do is use a quadtree, split the landscape up into patches and for each patch have various levels of detail.
eg when the camera is so far away ill display the patch like so, when its closer ill display it like so (with more tris)

lots of info about terrains at www.vterrain.org