Bonsai QTO (Quantity Takeoff) — Implementation Skill

Bonsai v0.8.x | Module: bonsai.bim.module.qto | NEVER use blenderbim.bim.module.qto

1. Quick Reference

Critical Warnings

• ALWAYS verify objects have mesh geometry before running QTO calculators. Empties, curves, and lights cause failures.
• ALWAYS ensure objects have an IFC class assigned via Bonsai before running QTO. Calculator functions query IFC properties.
• ALWAYS assign Pset_MaterialCommon.MassDensity BEFORE running weight calculations (get_net_weight, get_gross_weight).
• ALWAYS re-run QTO calculations after modifying geometry. Quantities are NOT live-linked to geometry.
• NEVER assume get_gross_volume() accounts for openings. Gross = original geometry WITHOUT openings. Net = WITH openings subtracted.
• NEVER use the legacy blenderbim module path. ALWAYS use bonsai.bim.module.qto.

Decision Tree: Which QTO Approach?

Need quantities for IFC elements?