Scan to BIM Explained: From Point Cloud to Revit Model
Renovating a building you only have old drawings of? Scan to BIM turns a laser scan into an accurate Revit model. Here is how it works and what to prepare.
In this article
Renovation and retrofit projects share one problem: the drawings you have rarely match the building you are standing in. Walls were moved, ceilings dropped, services added. Scan to BIM solves this by capturing the real building and turning it into a model you can design in.
This article explains what scan to BIM is, how the workflow runs from site to Revit model, and what to prepare so the result is useful from day one.
What is scan to BIM?
Scan to BIM is the process of converting a 3D laser scan (a "point cloud") of an existing building into an intelligent BIM model, usually in Revit. A scanner records millions of measured points on every visible surface. A modeler then builds walls, floors, openings, structure and other elements to follow those points, so the model reflects the building as it truly stands.
The result is not just a picture. Each element in the model is a real Revit object, so you can tag it, schedule it, section it and design against it.
Why not just measure by hand?
Hand measuring works for a single room. On a whole building it is slow, easy to get wrong, and gives you dimensions rather than context. A scan captures everything at once: out-of-plumb walls, uneven floors, ceiling heights that change, and the exact position of beams and openings. That means fewer surprises when construction begins and less time spent re-measuring on site.
The workflow, step by step
- Scan the building. A surveyor or scanning provider captures the interior and exterior and delivers the point cloud, commonly in RCP, RCS, E57 or LAS format.
- Prepare the cloud. The data is cleaned, aligned and, for large sites, split into manageable regions so Revit stays responsive.
- Agree the scope. Decide what gets modeled and to what level of detail. Not every pipe and bracket needs to be a model element.
- Model in Revit. Walls, floors, roofs, stairs, openings, columns and beams are built to follow the cloud, with levels and grids set up properly.
- Check against the scan. The model is compared to the point cloud to confirm it falls within the agreed tolerance.
- Deliver and hand over. You receive the Revit model, and usually a set of plans, sections and elevations extracted from it.
How accurate does it need to be?
Accuracy is a decision, not a default. A model for early feasibility can accept a looser tolerance than one used to fabricate steel or coordinate tight service routes. Agree three things up front:
- Tolerance: how close the model must be to the scan, for example a few millimeters or a couple of centimeters.
- Level of detail: which elements are modeled, and how much geometry each one carries.
- What is excluded: furniture, fine finishes and hidden services are typically left out unless you ask for them.
Putting these in writing prevents the most common disagreement in scan to BIM projects: the client expects detail the scope never included.
What you get at the end
- A Revit model of the existing building with levels, grids and clean, named elements.
- Floor plans, sections and elevations generated from that model.
- Optionally, a linked point cloud so your team can verify any dimension later.
Common pitfalls to avoid
- Scanning without a scope. A beautiful cloud with no agreed model requirements produces arguments, not drawings.
- Missed areas. Ceiling voids, plant rooms and roof spaces are often skipped. Tell the scanning team what the model must cover.
- Overmodeling. Modeling every irregularity makes the file heavy and slow. Model what the design needs.
- No coordinate plan. Make sure the scan and the model share a coordinate system, especially if other models will be linked later.
What to prepare before you start
To get an accurate scope and quote, gather the point cloud files, any existing drawings (even if they are outdated), the target Revit version, and a short description of what the model will be used for. If you only have rough scans or photos, say so; there are options at different levels of detail.
Next step
Architive builds Revit models from point clouds and from existing drawings, with a clear scope agreed before work begins. See how it works on our BIM and Revit services page, or send us your files for a free consultation and a practical recommendation.
