Based on the fact that "NPatches", or N-Patches, are a form of tessellation, and given this documentation from the official MSDN dev center, I believe these options, when set appropriately, allow for the tessellation of in-game objects. However, I have no idea whether these options work (I never knew DirectX 9 supported tessellation until recently), how the Gamebryo game engine, the engine on which Fallout: New Vegas runs, handles tessellation, or whether that's what these options even represent. I've tried tweaking those three options, but have yet to see any discernible difference.
Does anyone have any inkling as to what these options do?...