Where to Find 3-Models for Printing
Thingiverse – When you say 3-D printing files, this is the site that most people think of it. Easy to search, and almost every file posted is designed and optimized for fabrication via 3-D printing.
GrabCAD – GrabCAD is Thingiverse’s older, PhD holding brother. Designed as a site for engineers to share CAD files, GrabCAD models are generally capable of being used for 3-D printing, but additional optimization or repair might be needed.
Modification and Repair
-If you’ve got a file, and it’s not in a shape that you can use, there’s a few options.
NetFABB – A handy tool for chopping apart, inverting and resizing models. It also can convert files from one format to another, which is useful if you need to get a .STL file from another format. It’s available as freeware. Paid versions provide even more usability.
Microsoft STL Repair – If you have a file that won’t slice properly, or isn’t watertight, and causes issues during printing, give it a run through this free tool that NetFabb and MS developed together. This program is super useful since a lot of freely available 3d models aren’t always designed with printing in mind.