A360 VIEWER - Free online CAD Viewer
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
eDrawings Viewer - View, print, and review all types of eDrawings files Built-in Viewer
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.
Vesalius3D - Vesalius3D is a toolkit for visualization of patient specific anatomy
IGES2STEP - Freeware CAD file viewer for Windows XP/2000/NT