Open Asset Import Library (short name: Assimp) is a portable Open Source
library to import various well-known 3D model formats in a uniform manner.
The most recent version also knows how to export 3D files and is therefore
suitable as a general-purpose 3D model converter. See the feature list.

Assimp aims to provide a full asset conversion pipeline for use in game
engines/realtime rendering systems of any kind, but it is not limited to
this purpose. In the past, it has been used in a wide range of applications.