Autodesk FBX SDK
Autodesk FBX SDK 2016.1 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The program's installer is commonly called AdDLMgr.exe, DesignReview.exe or DWFViewer.exe etc.
We recommend checking the downloaded files with any free antivirus. The following version: 2011.3 is the most frequently downloaded one by the program users. This free software is a product of Autodesk, Inc. Autodesk FBX SDK lies within Photo & Graphics Tools, more precisely 3D Design.
From the developer:
Autodesk® FBX® asset exchange technology facilitates higher-fidelity data exchange between several Autodesk content creation packages—Autodesk® 3ds Max®, Autodesk® Maya®, Autodesk® MotionBuilder®, Autodesk® Mudbox™, and Autodesk® Softimage® software—and provides support for certain third-party and proprietary applications.
You may want to check out more software, such as Autodesk FBX Extensions SDK, Autodesk FBX Plug-in - QuickTime or Autodesk FBX Plug-in - Maya 2010, which might be related to Autodesk FBX SDK.