TF is a file extension used by an application called Autodesk Inventor. It is a CAD program for creating, designing and simulating 3D elements. It is commercial software developed by Autodesk, Inc. for systems from the Windows family.

TF files are used by this specialized tool to store projects created in it. This allows you to save an infinite document and reopen it at a later time and continue your work. This solution is also used to exchange projects between authors.