What each part of the building is actually made of

The join between the member the 3D builder draws, the line on the estimate and the row in the price list. A takeoff says 'Girt, 64 pcs'; a yard sells 2x6 SPF by the foot. USAGE_MATERIAL maps one to the other, and the BINDING IS THE PRICE.

Also called: usage to material · girt is 2x6 SPF · material binding · change the lumber · change 2x6 price once · what is a girt made of

1. 1Bound usages price from the catalogue and from the tenant's override of that catalogue row, so changing 2x6 SPF in Settings changes every girt, cripple and sill on every estimate at once.
2. 2Unbound usages fall back to their usage row — the ones with no single material behind them (a truss is fabricated to span and pitch, a door is a product) or that SmartBuild prices inside a package.
3. 3The bindings encode judgement, stated in the code: posts are the 3-ply 2x6 laminated column because it is what both tenants actually buy (758 priced lines vs 58) and what the engine draws; anything in ground or concrete contact is treated; purlins are 2x4 SPF and girts 2x6 SPF; wall and roof steel is the 29Ga AG panel, the commonest of the four gauges priced (2,415 lines).
4. 4materialForUsage() surfaces the bound material on the estimate line so the customer-facing description names the product.

• ◆Editing an abstract usage price when what changed is a material.
• ◆Estimate lines naming internal usages instead of products.