1.Sharecad.org
Free online 2D and 3D CAD viewer. It supports AutoCAD DWG/DXF, STEP, STP, IGES, IGS, STL, SAT (ACIS®), Parasolid (x_t, x_b), SolidWorks ™ (sldprt), PLT, SVG, CGM and other formats. With its help you can view your drawing or 3D model in any browser and from any device, including Android and iOS devices. ShareCAD - view files online anytime, anywhere!