Rawson Group · 2025–2026 · Flagship build
Takeoff Automation (5D)
Revit → Forma, end to end.
A production pipeline I built and own at Rawson Group (Daiwa House) that replaces the manual 2D-sheet takeoff with a deterministic, API-driven extraction from Revit to Autodesk Forma. Every quantity is traceable to a model element, a classification rule, and an APS call.
No LLM in the classification path.
PER_PROJECT
TAKEOFF
6–8 h → 2 min
end-to-end runtime
PORTFOLIO COVERAGE
120+
master home designs
ACTIVE MODELS
347+
Revit - live production
CLASSIFICATION
Rule-based
regex + trade code
map, auditable
01 · LIVE DEMO
End-to-end, in two minutes.
Single take. Revit model in, populated Forma Takeoff package out. The full pipeline — Model Derivative extraction, PropDB build, rule-based classification, APS POST — runs in roughly the length of a coffee break.
The same workflow used to take most of a day.
YouTube · unlisted·youtu.be/6w3Gy0p5Ci4·Source: ACC_Takeoff_Showcase_20260318_012610.webm (24 MB)
02 · Architecture
Revit → APS → PropDB → tt_map → Forma.
Every stage is a boundary I can name, version, and audit. The APS Model Derivative is the single read path into the model; PropDB is the SQLite EAV projection that makes the geometry/property graph queryable without re-opening Revit; tt_map is the deterministic classification layer that assigns each element a BOQ trade code; the APS Takeoff POST pushes the package into Forma with enough metadata to verify which Revit model version produced it.
03 · Code — the load-bearing parts
Three snippets. No mystery layer.
Every diagram stage above maps to a small, focused piece of Python. These are the three that carry the most weight: the EAV query engine that makes PropDB useful, the deterministic classifier that keeps the takeoff defensible at audit, and the APS POST that lands the package in Forma.
04 · Results
What the pipeline actually changed.
The runtime number is the headline. Everything below it is the reason the number is defensible at audit, and the reason IT sanctioned the pipeline under ISO 19650-5.
RUNTIME
6–8 hours → 2 minutes per project. Measured end-to-end from Revit model in to Forma Takeoff package populated.
ISO 19650-5 ALIGN
Three-tier APS account architecture, scoped service tokens, explicit audit logging. Declared in the BEP under Scripted Data Access.
PORTFOLIO REACH
Deployed across Rawson's 120+ master home designs and 347+ active Revit models. Same pipeline, same rules, no per-project forking.
EXCEPTION HANDLING
Unmatched elements are surfaced to a reviewer, never silently assigned. The rule set is versioned — classification v1.3 is repeatable in twelve months.
AUDITABILITY
Every quantity traces back to element → classification rule → BOQ code. No LLM classification in the core path. Defensible in a COBie handover audit.
OPERATING CADENCE
Pipeline reads only from Shared-status or higher containers. WIP models are rejected at the first check — by design, not by accident.