Updated: For an update movie tutorial please view our CAM/Gerber tool called FAB 3000, https://www.numericalinnovations.com/blogs/news/generating-a-3d-file-that-is-simply-the-thickness-of-the-pcb-with-component-locations-on-top-bottom
Here's a quick tutorial showing how to convert Gerber files to STEP. It also includes the ability to "crop out" a single component of the Gerber file for STEP export.
To try this yourself, request a free trial at: http://www.ace3000-3d.com