wavefront-obj-mode
An emacs mode for editing Wavefront obj files.
https://en.wikipedia.org/wiki/Wavefront_.obj_file
Install
Drop wavefront-obj-mode.el into your load path.
Then add to your init file:
(require 'wavefront-obj-mode)
(add-to-list 'auto-mode-alist '("\\.obj\\'" . wavefront-obj-mode))
(add-to-list 'auto-mode-alist '("\\.mtl\\'" . wavefront-obj-mode))