There is only one file type that uses the .NFF extension:
Neutral File Format
Generic 3D geometric design format developed in the 1990s; based on a "minimal scene description language," which describes the geometry and surfaces of objects, including the lighting placement and viewing angle.
NFF files are used for testing rendering algorithms and efficiency schemes. Although not needed for testing, NFF files may also include aesthetic object properties, such as color.
Updated: December 28, 2009