NIF stands for Net Immerse File Format. It is used for 3D models for state-save of game engine in action. NetImmerse (NIF) game engine is used in popular games like: Morrowind, DAoC, Freedom Force, Zoo Tycoon 2, Civ4 and Oblivion. NifSkope viewer is a free application to open, view, edit and save modified NIF files.
You can use it to quickly make changes to specific properties of a NIF file such as changing the texture, adding translucency and more. A 3D view of the contents of the NIF file allows you to preview your changes instantly. You can also create texture templates, and import & export OBJ files. Download NifSkope