Formats for the file exchange must fit a useable format. the default file type is .STL Aternatives that fit meshmixer such as .mix .obj .ply .amf .3mf .off can be posted with a note as to why they are not in .STL format. Any issue with posting a file should be raised to the admin team before reposting. Files of a specific type other than above will need approval from the admin team