IFC quantity takeoff, Cedar Flats Apartments Building 1, Cedar Flats, Oklahoma

Quantities from the architectural and structural IFC models by IFC class and type, with a classification check against types, geometry and the plumbing fixture schedule. 196 of 949 objects are flagged, and three errors change quantities that feed the estimate.

Architectural and structural models, IFC4Building 1, Levels 1–5, 30 unitsChecked against P-601 and A-101 to A-105Prepared Nov 5, 2026

Summary

IfcSanitaryTerminal · TOILETPAN

Water closet type holds 96 objects, but only 40 are water closets

Type “WC-1 Water Closet, Floor-Mount Tank” in the architectural model also carries 24 tub/showers and 32 lavatories on Levels 2–5. Level 1 is typed correctly. The fixture schedule on P-601 calls for 40 water closets, 40 lavatories and 30 tub/showers (30 baths and 10 powder rooms).

Action: retype 56 objects in the architectural model and request a new IFC export.

IfcBuildingElementProxy

100 chase and wet walls are missing from the partition takeoff

60 plumbing chase walls and 40 wet-wall furrings were exported as generic objects. Interior partitions come to 19,433 SF instead of 22,061 SF, which is 2,628 SF (11.9%) short.

Action: export them as IfcWall with PredefinedType PLUMBINGWALL.

A/S duplicates · IfcWall

40 CMU bearing walls appear in both the architectural and structural models

The architectural model’s “8" CMU Bearing Wall” coincides 100% with the structural model’s CMU-8 walls on all five levels. Summing both models puts CMU at 33,000 SF instead of 18,333 SF, which is 80.0% over.

Action: take masonry from the structural model and set the architectural walls to reference only.

Quantities and classification check

Click a takeoff line or a check rule to highlight its objects in the model, and click an object to see its IFC properties. Switch between quantities as delivered and as reclassified to see what the errors do to the estimate.

Quantities
Models
View
Area
0Objects in the models
0Takeoff lines (types)
0Flagged objects
0Fixture lines that match the schedule
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Classification check

Four rules run on all 949 objects. Click a rule to highlight its hits in the model.

Check against the fixture schedule

Plumbing fixtures counted by type and compared with the unit fixture matrix on P-601, plus the partition and CMU areas the estimate gets in each mode.

Quantities by IFC class and type

ModelUniformat IIIFC classPredefinedTypeTypeCount (EA)Length (LF)Area (SF)Volume (CY)Check

Wall area is length × height on one face, with no deduction for openings. Click a line to highlight its objects.

Sources and method

Sources

  • CFA_Bldg1_ARCH.ifcArchitectural model, IFC4: walls, doors, windows, plumbing fixtures and elevators.881 objects · 44.1 MB
  • CFA_Bldg1_STRUCT.ifcStructural model, IFC4: slab on grade, hollow-core plank, CMU bearing walls and stairs.68 objects · 18.9 MB
  • P-601_Plumbing_Schedules.pdfPlumbing fixture schedule with unit fixture matrix: 20 Unit A (one bath) and 10 Unit B (bath and powder room).1 sheet
  • A-101_A-105_Floor_Plans.pdfFloor plans for Levels 1–5, used to check object locations and room layout.5 sheets

Method

  1. Read both IFC files and grouped every object by model, IFC class, PredefinedType and type (IfcRelDefinesByType).
  2. Computed length, height, area and volume from each object’s geometry and assigned a Uniformat II (ASTM E1557) Level 3 code to each type. Fixtures, doors, windows and elevators are counted.
  3. Ran four check rules: R1 object name against type, R2 size and mounting height against the type’s nominal dimensions, R3 proxy objects with wall geometry and R4 walls that coincide at least 95% with a wall in the other model.
  4. Derived expected fixture counts from P-601: 30 baths (WC-1, LAV-1, TS-1), 10 powder rooms (WC-1, LAV-2) and 30 kitchens (SK-1).
  5. Built a reclassified takeoff with flagged objects moved to the proposed type and duplicates excluded.

Assumptions and limitations

  • Reclassification is a proposal. The models are unchanged, so the fix belongs in the architect’s model and a new export.
  • Wall area is one face, with no deduction for door and window openings. Estimating measurement rules apply after export.
  • Duplicates are found by geometry and IFC class. The architectural walls carry a CMU material and LoadBearing TRUE, which supports that they are the same walls as in the structural model.
  • R2 tolerances: 30% on footprint dimensions and 6 in. on the underside height above finished floor.
  • The check covers Building 1. MEP models, site work and amenity areas are not included.
  • CMU-8 bearing walls are coded B1010 (interior structural walls). If CMU-8 also includes exterior bearing end walls, those belong in B2010. The model data does not separate them, so the estimator should confirm the split with the structural engineer.
  • IfcWall, IfcSanitaryTerminal and IfcStair values were checked against buildingSMART’s IFC documentation. The PredefinedType values for IfcTransportElement, IfcSlab, IfcDoor, IfcWindow and IfcBuildingElementProxy and the property sets Pset_TransportElementCommon and Pset_BuildingElementProxyCommon were not, and the BIM coordinator should confirm them. STANDARD for IfcWall is valid in IFC4 but may be deprecated in IFC 4.3.