It sounds like you're looking for an easier way to handle roof designs in SketchUp without the steep price tag of premium extensions. While "cracked" software can seem like a shortcut, it often comes with hidden risks like malware or broken features that can derail your workflow.
And you want to ? Then respect the work of the developers who made Instant Roof. They spent thousands of hours coding that plugin. If you steal it, you are telling them their time is worth nothing.