# Methodology for Verification of Geometrically Complex Components Through Reverse Engineering
## 2 Materials and Methods
### Identification of Critical Factors Affecting Accuracy
To verify the deficiency illustrated in Figure 1, a reverse engineering method was employed, providing a detailed and precise assessment of geometric deviations between the actual weldment and its digital 3D model. Following an initial visual inspection, which can reveal fundamental defects, the weldment was measured using advanced reverse engineering technology. These devices enable accurate geometry capture, allowing the obtained values to be compared against the original CAD model. In this study, a Kreon ACE-7-30 articulated-arm 3D scanner was selected, capable of detecting even the smallest geometric deviations with high precision, ensuring that any discrepancies affecting assembly quality and accuracy are identified [15; 16]. The scanner was certified for a reach of 3000 mm, meaning it can perform measurements at distances up to this value with high precision. This certification is essential as it ensures that the device meets the quality and measurement reliability requirements set by the relevant standards and regulations. The verification results of its reliability can be seen in Table 1[17]. Figure 1: Shows dimensional and shape deviations in a cabin structure due to processing errors, material defects, and thermal deformations during welding, causing assembly issues. This process of comparing the measured parameters with the 3D model provides detailed information on any deviations that may result from improper welding fixture settings, thermal deformations of the material, or insufficiently precise welding parameter adjustments. These deviations may manifest as dimensional errors, which could affect subsequent assembly or the functional integrity of the weldment within the assembly. By identifying and quantifying these deviations, it is possible to determine precisely which aspects of the manufacturing process require adjustment, whether it involves modifying welding parameters, optimizing fixtures, or refining production processes. Reverse engineering thus not only confirms the existence of deficiencies but also provides specific data to improve the manufacturing process and minimize errors [18,19]. To improve access to the measured surfaces of the cabin weldment and optimize scanning angles, an elevated platform, as shown in Figure 2, was used. This setup ensured better visibility and reduced obstacles during the measurement process. Positioning the weldment at a more accessible height allowed for easier and more precise scanning of complex areas. The elevated platform also helped minimize potential errors from poor scanning angles, ultimately improving the accuracy and reliability of the measurements. This approach contributed to more efficient data collection and enhanced the overall quality of the inspection process. As shown in Figure 3, which displays the color deviation map, the inspection process involves selecting input values--specifically, the permissible tolerances based on the technical drawing documentation (in our case, \(\pm\)6 mm). These values are represented in green on the map, indicating that the measured deviations fall within acceptable limits. Blue areas on the map denote negative deviations, meaning that the measured point is below the required value. Conversely, red areas indicate positive deviations, signifying that the measured point exceeds the specified dimensional requirements. If the overall model exhibits deviations in red or blue areas that exceed the allowed tolerances, it indicates that the model is defective and requires adjustments or corrections in the manufacturing process to achieve the required precision and quality.