Assimp
The Open Asset Import Library is a mature cross-platform C++ importer that reads numerous mesh and scene formats into common materials, skeletons, animations, nodes, and texture references.
Why use it
Custom engines and offline tools avoid maintaining a parser per format, normalizing external assets before validation, optimization, baking, and conversion into runtime-specific data.
Where it fits
Find engines, frameworks, code libraries, version control, and production automation.
What to check
Broad format coverage does not mean identical support for every extension; test complex FBX files, material semantics, coordinate systems, and animation boundaries with real production assets.