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Terrestrial laser scanning (TLS) is a surveying method used for the precise digital capture of buildings and structures. A stationary laser scanner measures millions of points on visible surfaces and generates a three-dimensional point cloud. This point cloud serves as the basis for as-built plans, BIM models and digital twins.
Why is terrestrial laser scanning important?
- High accuracy: Millimetre-level capture enables reliable planning and as-built data.
- Complete documentation: Buildings are captured comprehensively through a digital as-built survey instead of only at individual measuring points.
- Fewer follow-up measurements: Relevant dimensions can later be evaluated directly in the point cloud.
- Digital processing: The data can be transferred directly into CAD, BIM and CAFM processes.
How terrestrial laser scanning works in practice
- Data capture: The scanner is positioned at several locations inside the building or outdoors and captures the surroundings using laser pulses.
- Registration: Individual scans are combined into a single point cloud using reference points or cloud-to-cloud methods.
- Quality assurance: Checkpoints, registration errors and tolerances are reviewed and documented.
- Data preparation: The point cloud is cleaned, structured and prepared for further use.
- Derivation of results: The data can be used to create floor plans, elevations, sections and other outputs.
Quality Criteria
- Documented accuracy and tolerances
- Complete coverage without relevant blind spots
- Clean registration of individual scans
- Traceable checkpoints and QA protocols
- Clear coordinate system and metadata
Common mistakes / misunderstandings
- Too few scanner positions lead to shadowing and data gaps.
- Missing quality checks can cause registration errors.
- Old as-built plans are adopted without being checked against measured data.
- Accuracy and level of detail requirements are not defined before the start of the project.
Terrestrial laser scanning vs. mobile laser scanning
Terrestrial Laser Scanning (TLS)
- Highest accuracy
- Stationary measurement positions
- Ideal for as-built documentation, BIM and renovation planning
Mobile Laser Scanning (SLAM)
- Faster data capture
- Moving capture while walking
- Lower accuracy, but higher area coverage
The right choice depends on the project goal, the required accuracy and the size of the building.
FAQ
How accurate is terrestrial laser scanning?
Modern systems can achieve millimetre-level accuracy, depending on the specific measurement task.
What is created from a laser scan?
Usually, the first result is a point cloud. This can then be used to create as-built plans, CAD models, BIM models or digital twins.
When is TLS particularly suitable?
TLS is especially suitable for renovations, conversions, listed buildings, complex building services and any situation where precise as-built data is required.