Hi. I'm Thepal. I come up with ways to "cheat" in order to do the extremely hard or impossible.
I was thinking aboutyour landscape problem. Here's my ideas:
Idea 1: some objects get drawn on top of items, others only show up if there is nothing there. Could you use that to your advantage? If the interior is in front of the player then simply don't draw the landscape mesh (on a per pixel basis) and if the window is on part of the screen then the landscape would show up just for that part (like how the light markers only show up if there is no world in front or behind them).
Issues with this: the windows are a part of the interior mesh; parts of models outside which are meant to be underground could prevent the landscape from displaying and therefore make it look weird. Also, the landscape nifs would need to be altered; may not be possible
Interesting thought, but since the windows are part of the interior mesh and there is no way to draw on a per pixel basis (at least, not without heavily modifying the closed-source engine).
Idea 2: could you make use of the alpha issues? Is it possible to have something show up only if you're looking through something translucent? It's possible to make things disappear... Maybe we can reverse it.
Issues with this: could cause landscape to show up through other translucent objects; working out how to mess with alphas; may not be possible
I don't think this is possible. Very cool idea, though.
To some extent, yes. And since we are dealing with actual meshes and not real landscapes, NifSE would be the way to go. I'm not sure about it being able to move individual vertices yet though.
NifSE would be the 'optimal' solution - and I have talked to the creator of NifSE about this, but NifSE, for the moment is not close to being capable of modifying individual vertices to such an extent.
How about letting the landscape clip and creating a region inside the interiors (shaped like the interior's outline? ) where the mesh would be invisible.
Uhhh... I don't think that would work either.
My current solution to this landscape issue is to modify the landscape itself - by adding in an alpha layer to the landscape textures, I can create transparency where the landscape intersects with the building(s). This would be relatively time-consuming, but it will produce the best results with the tools currently at my disposal. OBSE can likewise be used to modify NIF textures on the fly, so it would be easy to switch between the two textures for each landscape mesh.