Autodesk Navisworks offers a free version, Navisworks Freedom, which provides basic functionality for viewing and interacting with 3D models. While a portable version is not officially available, users can create one using third-party tools or by installing the software on a portable device. However, licensing restrictions and performance issues may limit the use of portable versions. Ultimately, users must weigh the benefits and limitations of each option to determine the best way to utilize Autodesk Navisworks for their specific needs.