Morpholio Trace - Morpholio Trace is widely called to be the dream software of the designers and architect.
A360 VIEWER - Free online CAD Viewer
Qlone - 3D scan any object with your iPhone or iPad
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.
DWG FastView - DWG FastView for Windows is a lightweight dwg/dxf drawing viewer and editor produced by Gstarsoft, no need of dwg format conversion, vector graph magnified without distortion and full compatible with AutoCAD DWG/DXF.
eDrawings Viewer - View, print, and review all types of eDrawings files Built-in Viewer