There are no current links to a free version of Instant Roof Pro, as the developer shifted to a fully paid model years ago. The Pro/Nui versions are the only options available today for new users.
Assign different pitches or slopes to individual eaves on the same roof structure for complex, asymmetrical designs. Step-by-Step Workflow: Creating Your First Roof Instant Roof Pro Sketchup Plugin
In summary, Instant Roof is a great starting point for basic needs. Instant Roof Pro was the previous paid version, offering enhanced capabilities over the free version. is the most current version and supersedes Instant Roof Pro, including all its features and adding many more. It is also a paid yearly subscription. There are no current links to a free