Scan to BIM: point cloud to BIM workflow, LOD levels, software and costs
Key takeaways
- Scan to BIM turns a laser-scanned point cloud of existing conditions into an object-based BIM model.
- Level of development (LOD) defines how much detail and information each model element carries; level of accuracy (LOA) defines how close it must be to reality.
- USIBD LOA bands run from LOA10 (coarser than 5 cm) to LOA50 (0–1 mm), and measured and represented accuracy are specified separately.
- Scope, not scanning, drives most scan to BIM costs: LOD, disciplines and building complexity decide the modelling hours.
- A deviation check of the model against the point cloud is the key quality control step before delivery.
What is scan to BIM?
Scan to BIM is the conversion of 3D laser scan data of an existing structure into a building information model, where walls, slabs, columns, pipes and other elements are modelled as intelligent objects rather than points. It gives designers, contractors and facility managers an accurate digital record of existing conditions to design against.
The input is a registered point cloud, usually millions to billions of points captured with terrestrial or mobile laser scanners. The output is a point cloud to BIM model built in BIM authoring software, often exported to the open Industry Foundation Classes (IFC) format.
This article covers the modelling process, LOD and LOA levels, software types and outsourcing costs. For the construction-phase workflow of producing as-built drawings from scans, see our companion guide to scan to BIM and as-built drawings.
How does the point cloud to BIM workflow work step by step?
A point cloud to BIM project runs from scope definition, through scanning and registration, to modelling and verification. Most failures trace back to an unclear scope at step one, not to the scanner.
- Define scope. Agree areas, disciplines (architecture, structure, MEP), LOD per element type, LOA, coordinate system, software version and deliverables, ideally in a BIM execution plan.
- Establish control. Set a survey control network with a total station or GNSS so the model sits on the project grid and levels.
- Scan. Capture all required areas, including ceiling voids and risers if MEP is in scope, with enough overlap for registration.
- Register and check. Combine scans into one point cloud, tie it to control, and report registration errors.
- Prepare the cloud. Clean noise, segment by level or zone and reduce file size for modelling.
- Model. Trace and fit elements to the cloud, from grids and levels to walls, slabs, openings, structure and services.
- Verify. Run a deviation analysis of model surfaces against the cloud and fix out-of-tolerance elements.
- Deliver. Issue native and IFC models, the registered cloud and a QA report.
Registration and cleaning are covered in more depth in our point cloud processing guide.
What are LOD levels in scan to BIM?
LOD, level of development, describes how much geometric detail and reliable information a model element contains, from a generic placeholder at LOD 100 to a detailed, element-specific representation at LOD 400. For existing-condition models, most scan to BIM projects are specified at LOD 200 to LOD 350.
| LOD | What the element shows | Typical scan to BIM use |
|---|---|---|
| LOD 100 | Massing or symbol only | Site context, feasibility |
| LOD 200 | Generic element with approximate size, shape and location | Space planning, early design, area measurement |
| LOD 300 | Specific element with accurate size, shape, location and orientation | Refurbishment design, coordination; the most common specification |
| LOD 350 | LOD 300 plus interfaces and connections to other elements | MEP and structural coordination, clash detection |
| LOD 400 | Detailed enough for fabrication and installation | Prefabricated retrofits, plant replacement |
| LOD 500 | Field-verified representation (used in some frameworks) | Facility management records |
Be specific: a single LOD for the whole model rarely makes sense. Our engineers usually recommend an element table, for example walls and slabs at LOD 300, ceilings at LOD 200, and main ducts and pipes over a stated diameter at LOD 300, with small services excluded.
What is LOA, and how does it differ from LOD?
LOA, level of accuracy, defines how closely measured data and modelled elements must match the real building, while LOD defines how much detail is modelled. A model can be detailed but inaccurate, or accurate but simple, so both must be specified.
The U.S. Institute of Building Documentation (USIBD) LOA specification uses five bands, stated at a 95% confidence level:
| LOA | Accuracy range | Example use |
|---|---|---|
| LOA10 | Coarser than 5 cm (user defined) | Rough massing |
| LOA20 | 15 mm – 5 cm | Space planning, general architecture |
| LOA30 | 5 mm – 15 mm | Refurbishment and coordination |
| LOA40 | 1 mm – 5 mm | Detailed structure, plant, prefabrication |
| LOA50 | 0 – 1 mm | Specialist industrial or heritage work |
The specification separates measured accuracy (the point cloud) from represented accuracy (the model). A typical specification is a point cloud at LOA40 with a model at LOA30, because modelled walls are idealised flat planes while real walls are rarely perfectly flat or plumb.
Which scanners and software do you need for scan to BIM?
You need a laser scanner suited to the building type, control instruments, registration software and BIM authoring software; most work is done with terrestrial scanners, supported by handheld SLAM for fast coverage.
Capture equipment
- Terrestrial scanners for the main structure and plant rooms. Our terrestrial 3D laser scanner captures up to 2 million points per second with HDR colour in a 4.4 kg body, a good fit for interiors and BIM existing conditions. For large halls and exteriors, the high-speed terrestrial laser scanner scans at up to 1000 kHz with a 360° × 282° field of view.
- Handheld SLAM for corridors, stairs, voids and fill-in areas at centimetre-level accuracy, using our handheld SLAM laser scanner.
- Scanning total station where scans must sit on tight control, such as tunnels, rail interfaces or structural monitoring; our scanning total station combines total-station measurement with 3D scanning.
Software categories
- Registration software: target-based and cloud-to-cloud registration, control adjustment, QA reports.
- Point cloud management tools: cleaning, segmentation, decimation and format conversion (E57, LAS/LAZ).
- BIM authoring software: the platform where the model is built and linked to the cloud.
- Scan to BIM plugins: semi-automatic extraction of walls, pipes, steel sections and floors.
- Deviation and model-checking tools: colour-mapped comparison of model surfaces against the cloud.
Fully automatic point cloud to BIM conversion is improving but still needs skilled modellers to interpret and check results.
What deliverables should a scan to BIM project include?
A complete scan to BIM project delivers the model in native and open formats, the registered point cloud, and documentation that proves accuracy. Ask for these in the contract:
- Native BIM model in the agreed software and version, with levels, grids and a clear element naming convention.
- IFC export for open exchange and long-term archiving.
- Registered point cloud in E57 or LAS/LAZ, plus a lightweight web or viewer version.
- 2D drawings generated from the model: plans, sections and elevations.
- Registration and control report with residuals and coordinate system details.
- Deviation report showing model-to-cloud differences against the specified LOA.
- Scope and exclusions log listing hidden, inaccessible or unmodelled areas.
Scan to BIM is also the first step towards a live operational model; our article on digital twins and reality capture explains how the model can be kept up to date.
How much do scan to BIM services cost?
Scan to BIM services are usually priced per square foot or square metre of floor area, with the total driven by LOD, number of disciplines and building complexity. Modelling from an existing point cloud commonly ranges from roughly USD 0.10 to over USD 1.00 per square foot (about USD 1 to 10+ per m²); site scanning is often priced separately as a day rate or per area.
| Cost driver | Lower cost | Higher cost |
|---|---|---|
| LOD | LOD 200 architecture only | LOD 350–400 with connections |
| Disciplines | Architecture | Architecture + structure + MEP |
| Building type | Open warehouse, repetitive offices | Plant rooms, hospitals, heritage |
| Accuracy | LOA20 | LOA40 with deviation reporting |
| Access | Empty, open building | Occupied, night work, ceiling voids |
Treat these figures as indicative; local labour rates and scope details move prices considerably, so compare quotes on the same written specification.
Should you outsource to a scan to BIM services provider?
Outsource modelling when you have occasional projects or lack trained modellers; keep scanning in-house if you work on existing buildings regularly, because capture quality and site knowledge are easier to control directly. Many survey firms scan themselves and use BIM modelling services for the modelling, especially for large MEP scopes.
When choosing a scan to BIM services provider, or comparing point cloud to BIM services and scan to BIM conversion services, check:
- sample models at the LOD you need, ideally in your building type;
- whether they work to LOD and LOA specifications and supply deviation reports;
- software versions, templates and family libraries they use;
- data security, especially for sensitive buildings;
- turnaround time and how they handle queries about unclear areas in the cloud.
Providers that market point cloud to BIM modeling services or general 3D BIM services vary widely in quality, so a short paid pilot on one floor is a sensible first step. If you want to bring capture in-house, our engineers can recommend a scanner and control kit for your building types; request a quote with your typical floor areas and LOD requirements.
Frequently asked questions
As built drawings vs record drawings: what is the difference?
As-built drawings are prepared by the contractor during and after construction to show what was actually built, including changes from the design, often as marked-up redlines. Record drawings are the final set compiled by the design team from the contractor's as-builts and site information, issued as the formal project record. Neither is a measured survey unless verified.
Are record drawings vs as builts accurate enough for renovation design?
Often not. Comparing record drawings vs as builts shows how documents depend on what contractors chose to record, and later alterations are rarely captured. For renovation, a laser scan and scan to BIM model provide measured existing conditions. Many designers use old drawings for reference only and design against a verified point cloud.
What are as constructed drawings?
As constructed drawings is the term used in the UK, Australia and some other regions for as-built drawings: drawings that show the works as actually completed, including deviations from the design. On infrastructure projects they are often based on survey measurements taken during construction, such as levels, alignments and the positions of buried services.
What LOD is used for scan to BIM?
Most scan to BIM projects are specified at LOD 200 to LOD 300 for architecture and structure, and LOD 300 to LOD 350 where services coordination or clash detection is needed. LOD 400 is used when prefabricated components must fit existing conditions. The best specifications set LOD per element type rather than for the whole model.
How accurate is a scan to BIM model?
The point cloud from a terrestrial scanner is typically accurate to a few millimetres, but the model is usually less accurate because real walls and floors are idealised as flat, plumb elements. Many projects specify the point cloud at LOA40 and the model at LOA30, around 5 to 15 mm, verified with a deviation report.
How long does scan to BIM take?
Scanning a typical 5,000 square metre office building takes about one to three days on site. Registration takes a day or two, and modelling from a few days to several weeks depending on LOD and disciplines. Architecture-only LOD 200 is fastest; full MEP at LOD 350 can take several times longer.
Can scan to BIM be fully automated?
Not yet for most projects. Software can automatically extract floors, walls, pipes and some steel sections, which speeds up modelling, but irregular geometry, clutter, partial visibility and element classification still need skilled modellers. Automation works best on regular buildings and simple elements, with human checking of every result against the point cloud.
Need equipment for this work?
Tell us the job, the country and the quantity. An engineer replies with a configuration and price within one business day. MOQ is one unit; OEM is available.
