From Just Solve the File Format Problem
STL. It uses various polygons, where STL uses only triangles.Wavefront OBJ (OBJ) is a 3D modeling format associated with Wavefront's Advanced Visualizer software, but used by other software as well, for similar uses as
.obj files are plain text. There is also a binary formulation of the format, with extension .mod.
OBJ files may reference external "material" (.mtl) files.
- Many 3D models are in Smithsonian set, in this and other formats