STM - BRT Tunnel - Jean-Talon / Pie-IX
Client / Collaborator
Société de transport de Montréal [STM]
Sector
Architecture, Infrastructure, Transport
Location
Montreal
Services
Relevé LiDAR
Mandate
DGTL was commissioned to digitize the pedestrian tunnel connecting the Pie-IX BRT stops and the future Pie-IX metro station (extension of the blue line), including all technical spaces and associated service areas. The objective was to accurately capture the conditions as built in order to update the existing Revit model.
All results had to be rigorously georeferenced and linked to the project's coordinate system to ensure seamless integration with the existing BIM environment and the models developed by the design team.
Mandate
DGTL was commissioned to digitize the pedestrian tunnel connecting the Pie-IX BRT stops and the future Pie-IX metro station (extension of the blue line), including all technical spaces and associated service areas. The objective was to accurately capture the conditions as built in order to update the existing Revit model.
All results had to be rigorously georeferenced and linked to the project's coordinate system to ensure seamless integration with the existing BIM environment and the models developed by the design team.
Proposition
To ensure perfect alignment with the ongoing project, DGTL relies on the existing primary control network: the coordinates provided by the project's surveying team serve as a geometric reference. We then propose a complete capture of the infrastructure using a combination of terrestrial LiDAR and mobile LiDAR (SLAM), attached to the same canvas, in order to cover the interior, exterior, and technical areas with continuity and without any missing areas.
Existing control network
We reuse the points and coordinates already established by the project surveyors to ensure a common reference base. This approach ensures spatial consistency between the point cloud, the existing Revit, and all disciplines (architecture, structure, mechanical, electrical).
Terrestrial LiDAR
We deploy terrestrial LiDAR to capture the “true terrain” geometry of volumes, walls, slabs, vaults, openings, and visible structural elements. The density and range of this type of scanning support reliable reading of shapes and efficient extraction for sections and elevations.
Mobile LiDAR (SLAM)
We supplement the capture with mobile LiDAR (SLAM) to ensure smooth and comprehensive documentation of passageways, technical rooms, premises, and complex transitions. This technology accelerates coverage and reduces blind spots, while remaining attached to the control framework.
Revit model update (as-built)
Using the captured data, DGTL methodically adjusts the Revit model to reflect the actual construction conditions. The modifications cover visible architectural, structural, mechanical, and electrical elements, in order to deliver a model that can be used for coordination, conflict resolution, planning, and future interventions.
Deliverables
Georeferenced point cloud in colour
A point cloud in colour, attached to the project control network, that serves as a measurable reference for validating geometry, checking clearances, extracting sections, and accelerating Revit and AutoCAD coordination between disciplines.
Quality report
A quality report that documents the attachment to the control framework and provides defensible statistics (deviations, residues, assembly parameters) to demonstrate the accuracy and traceability of the data used for modeling.
Updated Revit model (as-built)
A Revit model adjusted to site conditions, which facilitates coordination and decision-making. In particular, it allows the position and geometry of elements such as concrete walls and columns, openings, equipment, cable trays, ducts, and visible MEP components to be updated, resulting in a model that is consistent with the actual infrastructure built.
