| Step | Activity | Tool | Output |
|---|---|---|---|
| 1 | Model audit and validation | Navisworks / Solibri Model Checker / BIMcollab | Model audit report — listing missing elements, naming errors, classification gaps |
| 2 | Classification system mapping | Revit / ArchiCAD classification manager | All elements tagged with Uniclass 2015 or OmniClass codes; mapping table to CPWD/DSR items |
| 3 | Define extraction rules and parameters | Revit Schedules / Dynamo scripts / custom parameter sets | Extraction template defining: which parameters to extract, units, rounding rules, grouping logic |
| 4 | Element-wise quantity extraction | Revit Schedules / Navisworks Quantification / CostX / Cubicost | Raw quantity data in Excel/CSV — element ID, category, material, dimensions, quantity, unit |
| 5 | Data cleaning and consolidation | Excel / Power BI / Python scripts | Consolidated BOQ with grouped quantities by trade, floor, zone, and specification |
| 6 | Comparison with manual BOQ | Excel diff / CostX comparison / custom scripts | Variance report: BIM QTO vs manual BOQ — item-wise percentage deviation |
| 7 | Rate application and cost estimation | Excel / estimation software (Candy, CostX, WinQS) | Priced BOQ / cost estimate with BIM-linked quantities and market/SOR rates |
| 8 | Revision tracking and model updates | BIM 360 / ACC / CDE platform | Change log showing quantity impact of design revisions — auto-updated QTO |
| Step | Activity | Tool | Output |
|---|---|---|---|
| Substructure — Earthwork | Excavation, backfilling, disposal | Civil 3D / Revit Site | Volume of excavation (m³), backfill (m³), disposal (m³); classified by soil type |
| Substructure — Concrete | PCC, footings, raft, pile caps, grade beams | Revit Structure schedules | Concrete volume (m³) by grade; formwork area (m²); rebar weight (kg) |
| Superstructure — RCC | Columns, beams, slabs, stairs, walls | Revit Structure schedules | Concrete (m³), formwork (m²), rebar (kg) — by floor and element type |
| Masonry | Brick/block walls, partitions | Revit Architecture wall schedules | Wall area (m²), volume (m³), number of bricks/blocks; deduct for openings |
| Finishes | Plaster, paint, flooring, tiling, waterproofing | Revit room/space schedules + finish schedules | Floor area (m²), wall area (m²), ceiling area (m²) — by room/zone and finish type |
| MEP — Plumbing | Pipes, fittings, fixtures, tanks | Revit MEP pipe schedules | Pipe length (m) by diameter and material; fitting count; fixture count |
| MEP — Electrical | Conduits, wiring, panels, fixtures | Revit MEP electrical schedules | Conduit length (m), wire length (m) by size, switch/socket count, light fixture count |
| MEP — HVAC | Ducts, equipment, diffusers, insulation | Revit MEP duct schedules | Duct area (m²) by size, equipment count and capacity (TR/kW), insulation area (m²) |
| Step | Activity | Tool | Output |
|---|---|---|---|
| Revit Schedules | Native quantity extraction from Revit model using built-in schedules and material takeoff | Autodesk Revit | Excel export of element-wise quantities with parameters |
| Navisworks Quantification | Federated model QTO with measurement tools and item catalogues | Autodesk Navisworks Manage | Quantity workbook linked to 3D model; visual verification of measured items |
| CostX by Exactal | 2D and 3D quantity takeoff with live BIM links and revision comparison | CostX | Priced BOQ with automatic revision tracking; 2D measurement backup |
| Cubicost by Glodon | AI-assisted QTO from BIM and 2D drawings; strong in rebar and formwork | Cubicost TAS / TRB / TME | Detailed rebar schedules, formwork calculations, MEP quantities |
| Dynamo / Grasshopper scripts | Custom parametric extraction using visual programming | Dynamo (Revit) / Grasshopper (Rhino) | Custom formatted Excel/CSV with project-specific grouping and calculations |
| Power BI dashboards | Visual analytics and reporting of extracted BIM quantities | Microsoft Power BI | Interactive dashboards showing quantities by floor, zone, trade, element type |
| Step | Activity | Tool | Output |
|---|---|---|---|
| LOD 100 — Conceptual | Area-based estimation; no modeled elements, only massing | Revit massing / SketchUp | Order-of-magnitude estimate: ±30–50% accuracy |
| LOD 200 — Schematic Design | Approximate quantities from generic elements with approximate size and location | Revit with generic families | Preliminary estimate: ±15–25% accuracy |
| LOD 300 — Detailed Design | Accurate quantities from specific elements with correct size, shape, and location | Revit with specific families + schedules | Detailed BOQ: ±5–10% accuracy |
| LOD 350 — Construction Documentation | Quantities include connections, supports, and coordination elements | Revit + Navisworks + CostX | Construction-grade BOQ: ±3–5% accuracy |
| LOD 400 — Fabrication | Fabrication-level detail; rebar bar-by-bar, steel connections modeled | Tekla / Revit with detailing add-ins | Shop drawing-level quantities: ±1–3% accuracy |
| LOD 500 — As-Built | Verified field quantities matching actual construction | Point cloud + BIM model comparison | Final measured quantities for payment and asset records |