Generate hip roofs, rafters, and purlins quickly.

While 1001bit Tools (Freeware) is excellent for basic architectural needs (staircases, windows, walls), the Pro version offers: More advanced editing tools. A wider variety of stair and roof types. Parameter storage for efficiency.

If you are aiming for architectural accuracy and speed in SketchUp 2021, the Pro tools are essential. Conclusion

Spiral, circular, and dog-legged stairs with customizable treads and stringers.

The safest way to get the plugin is through the official developer site or the SketchUp Extension Warehouse.

Tools for creating terrain and site foundations. Understanding "Repack" Versions