The is like a Swiss Army knife for the architectural modeler. While it shows its age, its core tools—BZ Stair, BZ Profile, and BZ Linear Array—remain remarkably useful for rapid design development. For zero cost, you gain the ability to generate complex geometry that would otherwise take dozens of manual steps.
The is a legacy plugin collection (circa SketchUp 8 to 2017) designed specifically for architects and interior designers. Unlike heavy all-in-one extensions, BZ focuses on lightweight, parametric-like generation of common architectural elements. sketchup bz toolbar