Using Drones and Laser Scanning for As‑Built Surveys
In the age of digital transformation, traditional methods of building measurement and documentation are being replaced by more efficient, accurate, and scalable technologies. Manual measurements are slow, labor-intensive, and prone to errors. Today, terrestrial laser scanning (TLS) and drone-based surveys provide reliable as-built data within hours instead of weeks. The result? Fewer errors, lower costs, and dense point clouds ready for fast BIM modeling — reducing the preparation of models from weeks to just days.
What Is an As-Built Survey?
An as-built survey is a precise record of a building or site as it exists—not as it was designed. Unlike design drawings, as-builts capture all real-world changes that occurred during construction or over time.
They are essential for:
- Renovation and restoration projects
- Facility management and space planning
- Real estate transactions and legal documentation
- Clash detection in new design
- Post-construction verification
TLS and drones now replace weeks of tape-and-sketch fieldwork with dense point clouds and imagery that support accurate 3D models, 2D drawings, and BIM deliverables.
Terrestrial Laser Scanning: The Gold Standard
TLS remains the most reliable choice for precision as-built documentation. Tripod or mobile scanners rotate 360°, capturing millions of points per station in minutes.
TLS documents with unmatched fidelity:
- Interiors, circulation, and MEP systems
- Facades and roofs (even tall buildings)
- Structural elements and fine architectural details
- Large sites like campuses and industrial plants
Accuracy and Reliability of TLS Measurements
One of the main advantages of terrestrial laser scanning (TLS) is its high precision. Under favorable measurement conditions, deviations in the recorded point cloud can be as little as a few millimeters. This makes TLS indispensable wherever survey-grade accuracy is required – from façade and interior documentation to deformation monitoring and stockpile volume measurements.
Scientific studies confirm this precision – for example, a publication available on arXiv
shows that the accuracy of direct LiDAR point cloud measurements can be estimated at around 4 mm, which significantly facilitates the use of TLS in engineering and geodetic applications.
Why teams lead with TLS:
- Highest geometric fidelity for tight tolerances
- Works indoors, outdoors, and in GPS-denied areas
- Scales from small rooms to entire complexes
- Provides reliable data for clash detection and fabrication checks
Drone-Based As-Built Surveys
Drones equipped with RGB cameras or LiDAR rapidly collect geo-referenced imagery and point clouds from above.
Best for:
- Roofs, canopies, skylights, and hard-to-reach zones
- Large outdoor areas, roads, bridges, and rail corridors
- Topographic mapping and orthomosaic production
Quick example: A single RTK drone flight can capture a commercial building’s roof and facades in one session, producing a unified point cloud and orthomosaic for restoration planning, leasing, or insurance documentation.
Advantages of drones:
- Cover hundreds of acres in hours
- Improve safety by reducing work at height and near traffic
- High accuracy with RTK/PPK workflows and LiDAR payloads
- Excellent scalability for infrastructure and industrial projects
Best Results: A Hybrid TLS + Drone Workflow
Most U.S. contractors and BIM modeling teams use both methods. TLS delivers interior precision and façade detail, while drones provide roof and site coverage.
Fusing these datasets yields:
- Seamless 3D building and site models
- High-quality as-built drawings generated directly from point clouds
- Digital twins for renovation, operations, and asset management
- Smooth handoff into BIM and CAD environments
Key Applications
- Commercial real estate – leasing plans, insurance packs, tenant modifications
- Renovation & heritage – façades, roofs, sensitive architectural details
- Infrastructure – roads, bridges, railways, utilities, earthworks
- Residential – remodels, resale documentation, space planning
- Industrial & energy – clash detection, safety audits, and digital twins
Deliverables & Software Integration
Common formats:
- Point clouds – LAS, E57
- Mesh models – OBJ, STL
- 2D drawings – DWG, PDF
- BIM exchange – RVT, IFC
- 3D models \ BIM models – RVT (Revit), PLN (ArchiCAD), SKP (SketchUp), 3DS, FBX, DAE, IFC, OBJ
- Aerial mapping – orthophotos, DEMs
Challenges and Considerations
While these technologies offer powerful capabilities, it’s essential to consider:
- Weather: Drone surveys need good visibility and stable wind conditions
- Data Size: High-resolution scans produce large files
- Expertise: Requires trained professionals for data capture and processing
Choosing the right partner is key to ensuring accuracy, compliance, and a smooth workflow. At ScanM2, we specialize in delivering high-precision drone and laser scanning surveys, combining technical expertise with deep knowledge of industry standards. Whether you need a full-scale as-built model or just a roof scan, we ensure reliable results you can build on.
ScanM2 Project Example
ScanM2 carried out a LiDAR drone scanning project for a resort development covering 100 hectares of land. In just 1.5 days, a complete survey dataset was collected, and within two weeks the client received a full deliverable package: a 3D model compatible with ArchiCAD, 2D maps with elevation and tree density analysis, as well as precise measurements of distances from the lake and nearby roads. This allowed the investor to plan the placement of holiday cottages in an environmentally friendly way while meeting all formal requirements.
Why It Matters: Future-Proofing Your Project
As-built documentation isn’t just a technical requirement — it’s an investment in your project’s success. Whether you’re documenting for permits, insurance, design, or sale, accurate surveys:
- Reduce rework and costly surprises
- Improve communication with stakeholders
- Ensure regulatory compliance
- Add long-term value and traceability
Drone and laser scanning technologies deliver fast, scalable, and reliable results. They’re not just futuristic tools — they’re already transforming industries today.
Conclusion
Drones and laser scanning are now the industry standard for as-built surveys. Lead with TLS for interior and façade precision, then add drones for fast roof and site coverage. The result—faster projects, lower cost per square foot, and reliable BIM-ready deliverables for contractors, architects, and facility managers.
Frequently Asked Questions (FAQ)
How much does a 3D as-built survey include?
A 3D as-built survey provides a precise digital record of a building or site in its current state. Depending on the project requirements, it may include interior and exterior point clouds, façade documentation, roof scans, site mapping, and deliverables such as 2D drawings, 3D models, or BIM-ready data.
Are drones accurate for building surveys?
Yes. Drones with RTK/PPK and LiDAR achieve accuracy of up to 2–3 cm, which is sufficient for surveying roofs, facades, and large outdoor areas. For interiors or elements requiring millimeter-level precision, terrestrial laser scanning (TLS) is used. The best results come from combining TLS with drone data for a complete picture of the building and its surroundings.
What deliverables can I expect from an as-built survey?
Typical outputs include dense point clouds (LAS, E57), 2D drawings (DWG, PDF), 3D models (RVT, SKP, OBJ, IFC), and orthophotos or digital elevation models from drone flights. These can be directly integrated into CAD and BIM workflows.
When is an as-built survey needed?
As-built surveys are essential for renovation and restoration projects, facility management, real estate transactions, clash detection in design, and post-construction verification. They ensure that design teams, contractors, and owners work with accurate, up-to-date information.
