Scan to BIM Explained: Workflow, LOD, Costs and When You Need It

1. What scan to BIM means

Scan to BIM is a two-stage process. First, a 3D laser scanner records the existing building as a point cloud, a dense set of measured coordinates accurate to a few millimetres. Second, a modeller builds a Building Information Model, usually in Autodesk Revit, by tracing real geometry from that cloud into intelligent elements such as walls, floors, columns, doors, and pipes. The output is not a picture of the building. It is a measurable, editable model that carries data your design and construction team can use.

The point cloud is the evidence. The BIM model is the interpretation. Keeping both in the project means anyone can check the model against measured reality at any time.

2. The full workflow, step by step

1. Scope and plan: agree spaces, disciplines, target LOD, and coordinate system
2. Field capture: scan every required space with terrestrial and mobile LiDAR
3. Registration: align all scan stations into one coordinate system and check error
4. Survey control: tie the cloud to site control and a datum such as AHD and MGA2020
5. Cleaning: remove people, vehicles, and noise so the cloud is clear to model from
6. Modelling: build elements in Revit by discipline to the agreed LOD
7. QA: compare the model back to the cloud and document residual deviation
8. Handover: deliver the Revit model, the registered cloud, and an accuracy report

3. LOD levels explained

LOD describes how complete and reliable a model element is. It is a modelling contract, not a scanner setting. The scan can be millimetre-dense while the model is built only to the detail the project actually needs.

Most existing-building projects sit at LOD 200 for early planning or LOD 300 for documentation and coordination. LOD 400 is reserved for elements that will be prefabricated. For a deeper breakdown of LOD 200 against LOD 300, see our dedicated scan to BIM LOD guide.

4. What is included and what is not

A scan to BIM model captures visible and accessible geometry to the agreed standard. It does not automatically include hidden or concealed elements unless a dedicated scope is added.

• Included: walls, floors, ceilings, structure, openings, and visible services to the agreed LOD
• Optional add-ons: detailed MEP, finishes, furniture, and facade detail
• Excluded by default: concealed services behind linings, reinforcement, and internal insulation
• Excluded: legal boundary or cadastral information, which is a separate survey product

5. When architects and engineers need it

Scan to BIM earns its cost when the risk of working from wrong information is high. If a building has no reliable drawings, has been altered over decades, or has tight design tolerances, measuring it once removes guesswork from every later decision.

• Renovation and adaptive reuse where original drawings are missing or out of date
• Fitout and services upgrades that must thread through existing structure
• Vertical extensions and facade retention needing trustworthy structural geometry
• Heritage works where fabric must be recorded before any change
• Coordination-heavy projects where clashes are expensive to find on site

6. Typical costs

Capture and registration are often only 30 to 40 percent of a scan to BIM project. Modelling labour drives the rest, and it scales with LOD, the number of disciplines, and how much service detail is visible. A floor plate modelled at LOD 200 costs less than the same floor at LOD 300 because fewer elements are built to measurable detail.

If your internal team will model from the cloud, buying scan-only is usually best value. If you need the Revit model delivered on a deadline, bundled scan to BIM with a stated LOD avoids handover gaps. See the scanning cost guide for indicative bands and use the pricing calculator for a ballpark.

7. Software and formats

The model is normally delivered as a native Revit file. The point cloud is delivered in the format your team imports best, usually RCP for Revit teams or E57 for software-neutral exchange. State your target software up front so we export once in the right format. Our point cloud file formats guide explains the trade-offs.

8. How to scope your project

1. List the spaces or zones to be modelled
2. Set a target LOD per discipline
3. Reference your BIM Execution Plan, naming convention, and coordinate system
4. Decide whether you need the cloud only, the model only, or both
5. Consider a sample room or level to trial the approach before full commitment