Autodesk DWG TrueView - Get a free DWG viewer to view, open, edit, and convert .dwg files, the native file format for AutoCAD files. DWG Trueview includes DWG TrueConvert.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Autodesk Design Review - Design Review lets you view, mark up, print, and track changes to 2D and 3D files.
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
ZWCAD Viewer - Cross-Platform .DWG | .DXF | .DWT R12-2013 Viewer
ZBrush - ZBrush is a digital sculpting and painting software solution.