Office Tower Scan to BIM in Montreal
A Revit LOD 200 model that gave the design team a verified digital twin of an existing commercial office floor.
The Challenge
An architecture firm in Montreal was designing a full-floor renovation for a commercial tenant in a downtown office tower. The existing drawings were outdated - the building had been through several tenant fit-outs since original construction, and the current partition layout, ceiling grid, and MEP routing did not match any available documentation.
The architect needed an accurate Revit model at LOD 200 to begin design development, with particular attention to ceiling conditions and HVAC distribution. Without reliable as-built information, the design team was unable to move past schematic design with any confidence in the existing geometry.
The challenge was compounded by the occupied nature of the space - the existing tenant was still operating on-site during the documentation phase, requiring a capture method that would not disrupt daily business operations.
Our Approach
Two floors were scanned over 2 days - the target floor plus the floor above for MEP reference. 65 scan positions were captured per floor, including above-ceiling zones where tiles could be lifted. Scanning was coordinated with the existing tenant's schedule to minimise disruption, with the majority of capture work completed during off-peak hours.
The registered point cloud was modelled in Revit to LOD 200, including walls, doors, windows, columns, ceiling grid, exposed MEP, and major ductwork. The modelling team worked floor-by-floor, cross-referencing the above-ceiling scans to map HVAC distribution paths that were not visible from floor level.
An assumptions log documented areas where conditions required interpretation - for example, walls behind fixed furniture, concealed piping runs, and ceiling zones where tiles could not be safely removed. This log gave the design team a clear understanding of where verified data ended and professional judgment began.
Deliverables
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Registered point cloud
.RCP
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Revit model at LOD 200
.RVT
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Assumptions log
.PDF
Results
The design team began design development immediately upon delivery, saving an estimated two weeks compared to traditional field measurement. The model identified 3 instances where existing HVAC distribution conflicted with the proposed partition layout - conflicts that would have been discovered during construction without the BIM model.
By catching these coordination issues during the design phase rather than on-site, the project avoided costly change orders and schedule delays. The project moved to construction documents on schedule, with the as-built Revit model serving as the verified base for all downstream design work.
“The Revit model was exactly what we needed to move forward with confidence. The assumptions log was a nice touch - it showed us exactly where the team had to make judgment calls, which helped us prioritise our own site visits.”