**4. Case Study**

### *4.1. Validation on a Real High Formwork*

While the prior case studies show the effectiveness of the proposed method, a full in-site test on a real high formwork was carried out to evaluate the effectiveness of the proposed method. The dimensions of the high formwork were 5.5 m × 5.5 m × 6 m, consisting of 49 standard poles and 70 tubes. Both longitudinal and transverse spacing of pole are 0.8 m, while the lift height is 1.5 m. The formation of the high formwork is shown in Figure 20. The object provided an opportunity to validate the approach on a real structure.

As the results may have been influenced by the instrument position error between different point clouds, a control network was adopted to ensure that the horizontal position locates correctly within a millimetre. The error can be absorbed into +2 mm registration errors. Several scans from different viewpoints were collected so that the workflow efficiency could be evaluated in a real situation. Typically, a total of 10–15 min was spent at each position, including setup and scan time. The georeferencing process only took 5 min to complete. The point clouds of the high formwork are shown in Figure 21.

**Figure 20.** The photography of the high formwork.

**Figure 21.** Real point clouds of the high formwork.
