# 3D Point Cloud Dataset of Heavy Construction Equipment
## 3 Development of 3D-ConHE Dataset  
### 3.1 3D Point Cloud Data Generation and Collection  
It is not easy to collect a large 3D point cloud dataset to scan real heavy construction equipment working on earthworks and utilize it for ML and DL. In order to solve this problem, this research established the 3D-ConHE dataset using a heavy construction equipment diecast model with the same design and mechanical characteristics as the heavy construction equipment operated at the actual construction site. Therefore, this research procured diecast models representing five distinct types of heavy construction equipment in preparation for 3D scanning. These diecast models replicate their real counterparts in terms of design, mechanical features, and motion joints. However, each model comes in different scales, as detailed in Table 2, necessitating scale adjustments in post-processing after the 3D scanning procedure to match the real-life dimensions. Each construction heavy equipment diecast model chosen for this research has multiple motion joints (Figure 2). The selected five model types feature motion joints that enable movements in up, down, left, and right directions, offering a range of motions. However, for the reason of simplicity, this research streamlined the range of motion joints to MAX and MIN to account for the movements of construction heavy equipment during on-site operations. For example, Figure 2a depicts an excavator with four motion joints. Motion Joint 1 in Figure 2a represents the joint connecting the bucket and the arm. Motion Joint 2 pertains to the joint between the arm and the boom. Similarly, Motion Joint 3 denotesthe joint between the boom and the body, with no consideration for the bucket cylinder, arm cylinder, and boom cylinders. Finally, Motion Joint 4 corresponds to the joint section where the swing motor and swing bearing are installed. Additionally, rollers in Figure 2b,c were identified by the articulation joint as Motion Joint 1, although they were scanned separately due to differing scanning directions for Motion Joint 1. And the dump truck was scanned at varying heights for Motion Joint 1 in Figure 2d. Furthermore, graders in Figure 2e,f had different numbers of motion joints, each distinctively classified. Lastly, dozens in Figure 2g-i were separately scanned as they came in three different forms with varying numbers of motion joints and movement directions. Subsequently, the diecast model of a excavator, as depicted in Figure 2, was scanned by combining the movements of its motion joints, as showcased in Figure 3. Specifically, this research sequentially combined the motions of the model's motion joints during scanning to create data matching the movements of heavy construction equipment on construction sites. Figure 3 presents examples of the scanning methods employed by this research. Figure 3a1-a3 represent the combination of movements of Motion Joints 1 to 3, while keeping Motion Joint 4 stationary. Figure 3a4-a6 illustrate scans at 0\({}^{\circ}\), 45\({}^{\circ}\), 90\({}^{\circ}\), and 135\({}^{\circ}\) when the excavator's Motion Joint 4 completes a 360\({}^{\circ}\) rotation. Moreover, as the four angles (0\({}^{\circ}\), 45\({}^{\circ}\), 90\({}^{\circ}\), 135\({}^{\circ}\)) chosen for the excavator's Motion Joint 4 overlap with 180\({}^{\circ}\), 225\({}^{\circ}\), 270\({}^{\circ}\), and 315\({}^{\circ}\), no additional scans were conducted outside these four angles. As depicted in Table 3, the number of scans for each model was calculated, considering the motion joints of the models and the joint combination characteristics described earlier. As a result, the 3D scanning process was carried out and streamlined into a total of 669 movements, as detailed in Table 3. Specifically, the number of scans for excavators was notably higher compared to other diecast models due to the greater number of motion joints in excavators. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Types of** & **Classification in** & **Diecast Model** & **Scale** &