Online CAD viewer is described as 'Free online CAD viewer. Upload obj, .step, .stp, .igs, .iges, .stl. files and visualize them directly in the navigator. PC, Tablet or Mobile, no plugins or Flash are required'. There are four alternatives to Online CAD viewer, not only websites but also apps for Windows. The best alternative is Online 3D Viewer, which is both free and Open Source. Other great sites and apps similar to Online CAD viewer are STP Viewer (Free), 3D Viewer Online (Freemium) and CAOdrive (Free).
View, Measure, Share and Embed 3D models and 2D drawings directly in your browser. No installation required, works on computers, smartphones and tablets. Files supported : STP, IGS, STL, PLY, OBJ with MTL, DXF, DWG