A: Never. The only "permanent free" tools from Autodesk are the Design Review (DWF viewer) and Fusion 360 for Personal Use . Navisworks is a premium enterprise tool.
If you need to test the software for a professional project, Autodesk offers a comprehensive free trial of Navisworks Manage. : Typically 30 days.
Click "View Downloads." In the version dropdown menu, specifically select Download Method:
Because Autodesk often highlights the most recent version, you may need to navigate through your Autodesk Account to find 2021: Log into the Autodesk Account portal Locate Product: Go to "All Products and Services" and find Navisworks Manage Select Version: