FREE Step file Viewer - STP Viewer 2.3
https://stpviewer.comSTP Viewer is a software tool for viewing international STEP standard files. STEP files (.stp) for 3D and assembly are often used by all major mechanical CAD systems. With our absolutely free STP Viewer you can easily open 3D files (*.stp), rotate them and perform some basic actions like: zoom, rotate, move or change skin.
Free Online File Viewer - Autodesk
viewer.autodesk.comAutodesk Viewer makes it easy to share views of your designs and collaborate remotely. Autodesk Viewer supports most 2D and 3D files, including DWG, STEP, DWF, RVT and Solidworks. Learn more... Get feedback faster. Quickly get the feedback you need with Autodesk Viewer’s lightweight annotation and drawing tools. Autodesk Viewer is free to use.
Autodesk Viewer | Free Online File Viewer
https://viewer.autodesk.comAutodesk Viewer makes it easy to share views of your designs and collaborate remotely. Autodesk Viewer supports most 2D and 3D files, including DWG, STEP, DWF, RVT and Solidworks. Learn more... Get feedback faster. Quickly get the feedback you need with Autodesk Viewer’s lightweight annotation and drawing tools. Autodesk Viewer is free to use.