If you want to create a 3D model in STL format or edit an existing STL file in Windows 11/10, use these free STL editors.

This post lists down the best free 3D File Viewer software for Windows 11/10 to view and analyze 3D models & STL, etc, files.

An imported STEP file is converted to a triangle mesh on import (making it much like a typical .stl or .3mf file) which means that slicing all happens as one would normally expect.