BIM quantity and cost change tracker
A BIM revision-analysis system for comparing IFC models, calculating selected quantities, mapping cost items, and explaining quantity and cost changes between versions.
Project definition
Problem statement
Design revisions can add, remove, resize, or reclassify model elements, and a total-cost difference alone does not explain which model change caused it.
The engineering problem is to match elements across IFC revisions, calculate selected quantities consistently, map them to versioned rates, and maintain traceability from every cost difference back to model geometry and assumptions.
Project objectives
- Validate and catalogue selected IFC building models and revisions.
- Match unchanged, modified, added, and removed elements using stable and fallback rules.
- Calculate documented quantities for selected structural and architectural element types.
- Map quantities to versioned work items, units, waste factors, and rates.
- Explain quantity and cost changes visually with exceptions for manual review.
System design
System modules
Model intake
Validates IFC schema, units, storeys, element identifiers, classifications, geometry, and revision metadata.
Element matcher
Uses stable identifiers and geometric or property similarities to classify revision changes.
Quantity engine
Calculates selected length, area, volume, count, and derived quantities under versioned rules.
Cost mapper
Links model elements and quantities to work items, units, rates, factors, and cost versions.
Change dashboard
Highlights changed elements in 3D and traces quantity and cost differences to elements and rules.
Methodology
System workflow
- 01Load baseline
The student imports a prepared IFC model, quantity rules, classifications, and rate schedule.
- 02Calculate baseline
The system validates the model and stores element-level quantities and mapped costs.
- 03Load revision
A second IFC model is validated and matched against the baseline.
- 04Review changes
Added, removed, modified, unmatched, and reclassified elements are shown for confirmation.
- 05Compare impact
Accepted changes recalculate quantities and costs with complete element and rule traceability.
Demonstration scenario
A revised building model changes slab thickness, removes two walls, and adds four doors. The viewer colours each change, the quantity table shows the concrete and masonry differences, and the cost view traces every amount to its model element, rule, unit, and rate version.
Engineering
Technical architecture
- Web application
- Nuxt and Vue with Three.js for model viewing, filters, revision highlights, quantity tables, and cost comparison.
- BIM API
- FastAPI for model jobs, element records, matching, quantities, rates, changes, and exports.
- Data layer
- PostgreSQL for model versions, elements, properties, quantities, work items, rates, matches, and issues.
- IFC processing
- Python and IfcOpenShell for schema access, geometry, properties, units, and deterministic quantity rules.
- Verification
- Prepared simple models with manually checked quantities, known revision changes, and unit-conversion tests.
Testing
Evaluation
Evaluation measures
- IFC element import and unit-normalisation correctness
- Element matching precision across prepared revisions
- Quantity error against manually verified reference models
- Correct classification of added, removed, modified, and unchanged elements
- Cost difference traceability and agreement with prepared calculations
- Processing and viewer response time across model sizes
System boundaries
- The first version supports documented IFC schemas, element classes, property conventions, and quantity rules.
- Automatic matches and quantities require professional review before contractual use.
- Rates are prepared examples and not current tender, market, or government schedule values.
- The system does not replace a quantity surveyor, BIM coordinator, or contractual measurement process.
Included
- 01IFC model viewer and revision-comparison interface
- 02Element matching, quantity, cost, and change modules
- 03Visual change, exception, and cost-impact dashboards
- 04Prepared BIM revisions, rate items, and validation results
- 05Complete source code in a private GitHub repository
- 06Complete project documentation with synopsis, abstract, methodology, BIM workflow diagrams, quantity results, screenshots, and conclusion
- 07Setup and usage guide
Project record
No buyer information is collected on this page.
- Permanent project ID
- GP-CV-188VCV5
- Catalogued
- 21 Aug 2026
- Completed
- Pending
- Verified
- Pending
- Demonstration
- Added when ready
Handover
After purchase
- 01Payment is confirmed
The project is marked unavailable and cannot be purchased again.
- 02Repository access is granted
The buyer's submitted GitHub account receives access to the private repository.
- 03The purchase record is delivered
The certification sheet is prepared from the reviewed buyer details and sent privately by email.