Easy EDA PRO is an application for making PCB from idea to production. It's free.
This application is free for making STL and you can take a license for exporting or importing others files. License for one month or more.
This application is a low level of Ansys-SpaceClaim tools. link
link : https://www.rs-online.com/designspark/mechanical-software
PrusaSlicer a Free and Open Source application for 3D printing from STL file.
Run with Prusa Printer and others printers.