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Key Points
What Is Scan-to-BIM?
Scan-to-BIM uses a registered point cloud to model selected parts of an existing building or site. The cloud holds measured points; the BIM model interprets them. Agree which elements to model, their detail and permitted deviation from the cloud. Also define coordinates, file standards, exclusions and review checks. State Level of Development (LOD) and, when used, Level of Accuracy (LOA) requirements in the scope.
Our Approach
How we help your team
Your team needs a model that represents the elements relevant to its design and coordination work. We agree the model content, detail and tolerances with you, so the scope reflects how the BIM will actually be used.
We first establish the registration quality and coordinate basis. We then model the agreed elements and compare them with the cloud. The review uses the specified tolerances and file requirements. We state what is excluded and which conditions could not be verified.
Part 1 of 7
How the point cloud and BIM differ
The point cloud contains sampled surfaces with irregularity, noise, occlusions and gaps. A BIM author chooses which visible conditions become walls, floors, structural members, equipment, pipes or other objects. Standard families and idealized geometry cannot reproduce every dent, bow or edge exactly, so modeling rules must be agreed.
The model may be intended for background coordination, renovation design, quantity planning or a facility workflow. Those uses do not require identical content. Starting with the intended decision prevents unnecessary modeling while protecting the elements that matter.
Part 2 of 7
Define modeled categories and limits
A Scan-to-BIM scope should list the building systems, geographic areas and element sizes to include. For MEP work, it may define which pipe diameters, ducts, equipment and supports are modeled. For architectural work, it may specify walls, floors, ceilings, doors, windows and visible structure.
It should also state exclusions: concealed systems, inaccessible rooms, small components, loose furniture, insulation geometry, labels or non-geometric data. A model is easier to trust when users can tell what was deliberately omitted.
Part 3 of 7
Use LOD as a communication framework, not a substitute for scope
The BIMForum Level of Development Specification helps teams describe the content and reliability of model elements at different stages. It is useful for setting expectations, but a project still needs element-by-element requirements. Saying only “LOD 300” does not identify which systems, attributes, tolerances or existing-condition irregularities matter.
A strong model element table combines the LOD expectation with categories, minimum sizes, geometric treatment, information fields and permitted uses. That gives the modeler a testable brief and the recipient a clear basis for reliance.
Part 4 of 7
Separate LOD, LOA, capture quality and model tolerance
LOD and LOA answer different questions. The BIMForum Level of Development framework communicates the content and reliability of modeled elements. The U.S. Institute of Building Documentation Level of Accuracy specification provides a framework for specifying and reporting the accuracy of represented existing conditions. Neither term, by itself, defines the complete capture, registration or modeling scope.
Scanner specifications describe performance under stated conditions; field capture quality also depends on range, surface response, geometry and environment. Registration quality addresses how scan positions align. Model tolerance addresses how selected model geometry is compared with the registered cloud. A technically complete brief keeps those requirements distinct and identifies the evidence used to accept each one.
Scroll horizontally to see all columns
| Requirement | What it communicates | What the project should state |
|---|---|---|
| LOD | Model element content and reliability | Categories, information, permitted uses and element-by-element expectations |
| LOA | Specified and reported accuracy of represented existing conditions | Applicable class or requirement, tested elements and reporting method |
| Registration quality | How scan positions and control align | Method, control basis, checks and acceptance evidence |
| Model tolerance | Permitted model-to-cloud deviation | Elements, sampling method, exceptions and acceptance threshold |
Part 5 of 7
Set coordinates before modeling
The registered cloud and destination BIM must share a deliberate coordinate strategy. The team should identify units, vertical datum or project elevation, rotation, survey point, internal origin and any known control. Large real-world coordinates may require a coordinated local workflow to keep authoring software stable.
A known-point check should be performed after linking the cloud and again before delivery. Moving a point cloud link by eye can create a model that looks aligned in one view but cannot coordinate reliably with other disciplines.
Part 6 of 7
Modeling tolerances need an acceptance method
A tolerance statement should distinguish capture quality from modeling deviation. It should say how representative model surfaces will be compared with the registered cloud, which elements receive tighter treatment and how irregular existing geometry is represented. One universal millimeter value is rarely appropriate for every category and distance.
Useful QA includes section cuts, orthographic overlays, deviation views, known-point checks and targeted review of intersections or clearances. The review should sample the full model, not only the easiest planar areas.
Part 7 of 7
Plan the delivered BIM package
Confirm Revit or IFC version, worksets, naming, families, phases, levels, shared coordinates and linked reference files. Decide whether the point cloud accompanies the model and whether sheets, views or a model review report are included.
The delivery notes should state the capture date, included areas, coordinate basis, modeled categories, exclusions and known limitations. That context prevents the model from being treated as more complete than the source data or scope allows.
The point cloud is the captured reference; the BIM is a scoped interpretation. Define where that interpretation begins, how it is checked and what users may rely on.