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.
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
Autodesk Design Review - Design Review lets you view, mark up, print, and track changes to 2D and 3D files.
A360 VIEWER - Free online CAD Viewer
LiteCAD - Create, edit, view, and print 2D CAD drawings using the file formats: dxf, dwg, shp ;Download-Size...
ODA Viewer - ODA Viewer is a web-based software solution that allows you to view the files based on ODA format and you can easily zoom the file for detail visualization.