This free STL viewer is a WordPress plugin to easily display 3D files on your blog. It is implemented by using a simple shortcode. The plugin is based on WebGL. The features are very limited when compared to other 3D viewers on this list: You can freely zoom and rotate the object in any direction. The plugin was last updated in 2015; it can only be used once per page. Also, large files will slow the STL viewer down. On the plus side, the viewer is fairly fast with smaller 3D objects.