1. The direct answer
For a single scan, a professional terrestrial scanner such as the Trimble X7 measures points to roughly +/-2 mm at ranges out to tens of metres. That is the point accuracy from one tripod position. Real projects need many positions stitched together, and once those scans are registered and tied to survey control, the accuracy you can rely on across an entire building is typically +/-3 to 5 mm. This range suits BIM LOD 300 modelling, renovation design, structural assessment, and heritage documentation.
Accuracy is not a single number from a brochure. It is the result of the scanner, the registration method, the survey control, and the site conditions working together. A good provider reports the achieved accuracy with the deliverable rather than quoting only the best-case sensor figure.
2. Accuracy versus precision
These terms are often confused and they mean different things. Accuracy is how close a measurement is to the true value. Precision is how repeatable measurements are when you take them again. A scanner can be precise but inaccurate if it is consistently off by the same amount, and accurate but imprecise if results scatter around the truth. Reliable survey work needs both.
| Term | What it measures | Why it matters |
|---|---|---|
| Accuracy | Closeness to the true value | Determines if the model matches reality |
| Precision | Repeatability of measurement | Determines consistency between scans |
| Resolution | Spacing between captured points | Determines how fine the detail is |
3. What drives accuracy on a real job
- Registration quality: how well separate scans align into one cloud
- Survey control: tying the cloud to known points and a datum such as AHD and MGA2020
- Range and angle: accuracy reduces at long range and on steep grazing angles
- Surface type: dark, wet, or highly reflective surfaces return weaker data
- Environment: vibration, heat haze, and moving objects add noise
4. Resolution is not the same as accuracy
Resolution is the spacing between points, which controls how much fine detail the cloud captures, such as a small bolt head or a moulding profile. A high-resolution cloud can still be inaccurate if registration or control is poor. Conversely a well-controlled cloud at moderate resolution can be highly accurate. Match resolution to the smallest feature you need to measure, and rely on control and registration for accuracy.
5. Accuracy by application
| Application | Typical accuracy needed | Achievable with LiDAR |
|---|---|---|
| BIM LOD 300 renovation | +/-5 mm | Yes |
| Structural assessment | +/-3 to 5 mm | Yes |
| Heritage documentation | +/-2 to 5 mm | Yes |
| Clash coordination | +/-5 to 10 mm | Yes, comfortably |
| Large-area aerial terrain | +/-20 to 50 mm | Yes, by drone |
6. How we verify and report accuracy
We register every scan with documented error statistics, tie the cloud to survey control where the project requires it, and check the final model against the cloud. The handover pack includes an accuracy report so you can see the achieved figure rather than trusting a sensor specification alone. A registered surveyor is involved where boundary or control work is needed.
7. Getting the accuracy you need
- State the tolerance your deliverable must meet
- Tell us the coordinate system and datum if your model must align to site control
- Identify the smallest feature you need to measure so we set resolution
- Flag reflective, wet, or moving elements that affect data quality
- Ask for the accuracy report so the achieved figure is documented
For pricing against a given accuracy and area, see our scanning cost guide and try the pricing calculator, then send plans for a fixed written quote.