Introduction
Collab Digital Twins (CDT) is an open-source, browser-based platform for working with buildings, sites, point clouds, datasets, and live sensor data on a single interactive map. It bridges BIM and GIS using open standards, so you can move from a national map view down to a single IFC element without leaving the browser or switching tools.
CDT is used to view federated BIM models, monitor sensor feeds, browse open data, and coordinate work across teams.
Start here
Three audiences read these docs. Pick the path that matches what you want to do — each section is self-contained and links to the others where relevant.
End user / operator → You signed in to CDT and want to view buildings, browse open data, monitor sensors, or collaborate with a team. Start with the Quickstart — a 30-minute walkthrough from sign-in to your first uploaded model.
Developer / integrator → You want to extend CDT with a plugin, integrate it with another system, or contribute to the core. Start with the Developer Introduction, then the Architecture Overview and Plugins.
Self-hoster / deployer → You want to run CDT on your own infrastructure or evaluate a hosted deployment. Start with the Deployment Overview and the Environment variables reference.
What CDT is
CDT is infrastructure for managing the relationship between a physical environment and its digital representation over time. The platform combines:
- Three integrated viewers — a MapLibre-powered web map, an IFC BIM viewer (That Open Engine), and a Potree point cloud viewer — sharing a single coordinate system so a building uploaded in 3D appears in the right place on the map.
- Open data integration — a federated catalogue of national, provincial, and municipal data portals, fetched live and overlaid on the map.
- Live data feedback loops — IoT and sensor feeds linked to BIM elements or anywhere in the map, so design models evolve into operational digital twins.
- Multi-tenant collaboration — organizations, role-based permissions, threaded comments, and BCF issue tracking.
For background, the Concepts section explains digital twins, BIM, GIS, point clouds, and the open standards CDT builds on.
What CDT is not
CDT is not a BIM authoring tool — it does not replace Revit, Archicad, or Tekla. It is also not a desktop GIS — it does not replace QGIS or ArcGIS Pro. CDT is a federation, visualization, and collaboration layer that sits above those authoring tools and consumes their outputs (IFC, GeoJSON, LAS).
If you are evaluating CDT against alternatives, see CDT vs alternatives.
Principles
CDT is built around four principles that shape the platform:
- Open standards — interoperability over proprietary lock-in (IFC, GeoJSON, LAS, BCF, IDS, OGC services).
- Open source — transparent, community-driven development.
- Browser-native — no specialized software to install.
- Multidisciplinary — designed for stakeholders across BIM, GIS, planning, and operations.