Free Viewer, for Revit, Inventor, AutoCAD, SolidWorks, Catia and over 50 other formats
The Autodesk Viewer is extremely useful. It is free, but requires the user to sign up for an Autodesk account. Once signed in, simply drag and drop your file to view online.
The viewer supports the following formats:
3DM 3DS ASM CATPART CATPRODUCT CGR COLLABORATION DAE DGN DLV3 DWF DWFX DWG * DWT DXF EXP F3D FBX G GBXML IAM IDW IFC IGE IGES IGS IPT JT MAX MODEL NEU NWC NWD OBJ PRT RVT ** SAB SAT SESSION SKP SLDASM SLDPRT SMB SMT STE STEP STL STLA STLB STP STPZ WIRE X_B X_T XAS XPR
* Object-enabler viewing support only for AutoCAD® Architecture, AutoCAD® Plant 3D, and AutoCAD® Civil 3D. ** Files from Revit®