Factory files are the method used by Simplify3D to package everything you need to re-create your current session. We save the 3D models, placement details, manually placed support material, and build operations all to a single file. And better yet, we use a great compression method to save space on your hard drive! A .factory file is a great way to share builds between people who have similar printers. You could even save an entire project with several models, multiple build platters, and different slicing settings all to a single location. Imagine handing someone a single file that contained everything needed to print a complete Reprap Mendel kit!