Downloading Truss+RT 2015.1 from our website was free. The most popular version among Truss+RT users is 2015.1. The actual developer of the program is AGA CAD, LLC. Truss+RT lies within Photo & Graphics Tools, more precisely 3D Design.
From the developer:
Truss RT is a new solution for Autodesk Revit with a completely new view to design of truss system in Revit. Truss RT allows structural designers to quickly develop their truss projects in one platform. With configurable 3D truss system grid that is built in Truss RT, you can easily make a whole truss system at once. That allows designer to make fast design of common roof systems.
You may want to check out more software, such as Riptide, 3D Studio VIZ R3 or P-CAD 2004 Viewer, which might be related to Truss+RT.