There are 2 file types use the .TRI file extension:
1. FaceGen Polygonal Model File
3D model file created by FaceGen, an application used to create 3D human faces; contains a polygonal mesh for a human head; may also contain morphs, which are used for facial animations; often used for creating video game characters.
TRI files are used by Bethesda Softworks video games such as FallOut 3 and The Elder Scrolls IV: Oblivion.
Updated: March 12, 2011
2. Triangle Mesh File
3D mesh file created in the text-based TRI format; stores the mesh using x, y, z coordinate vertices and triangular polygons, which reference the declared vertices; used for constructing surfaces for 3D models.
There are some variations of the TRI file format, but the most basic version contains a one-line header followed by the vertices and triangles, where the header specifies the number of vertices and triangles.
TRI files are often used by scientific visualization or molecular modeling applications.
Updated: July 25, 2018