From Creation Kit
The model files are stored in a Gamebryo format called NetImmerse File format, which can be rendered with a Texture File or as is. These files are also commonly referred to as a Mesh, NIF, or NetImmerse File.
- Autodesk 3ds Max
- There are other software projects that provide tooling for working model files.
- The .nif file extension stands for Net Immerse File format.