ref: 0f0a9514ccabd558e9b6610e7c6150a69e6f9bcd
dir: /spec/
http://paulbourke.net/dataformats/obj https://people.sc.fsu.edu/~jburkardt/data/obj/obj.html https://paulbourke.net/dataformats/mtl/ https://www.loc.gov/preservation/digital/formats/fdd/fdd000508.shtml https://people.computing.clemson.edu/~dhouse/courses/405/docs/brief-obj-file-format.html