## 4 Implementation and Results
### Implementation  
Company T, located in Pyeongtaek, Korea, manufactures assembly line automation facilities and specialized equipment (piston insertion robots, valve finishing devices). In fact, there are several facilities and various robots available for use, but in this study, as shown in Figure 9, one 7-axis robot arm was used to model a physical factory environment. Data collection was required for designing the 3D VR production of the robot arm, and a 2D information product drawing, automated mechanical equipment 3D CAD information, and photo base mapping were conducted. Modeling data, including layers of components of each automated mechanical device and layers of each component, were collected. In the drawing of the acquired automation machine, the storage extension conversion was carried out through an inverter, and the layer was parted in the design program to form a part-oriented layer. Upon completion of the extension conversion, it was loaded into a real-time engine after being converted to general data such as IGS, OBJ, and 3 DS. Further, by applying the Surface Name, a preparation step for material and baking was prepared. After defining the material of the robot arm based on an image, VR content sets on the same scale as actual equipment are configured, and graphic performances such as unnecessary polygons and high-calculated material improvement are optimized. CAD design files of real-world physical automation machines are converted to 3D objects. CAD design files exist in various formats, but they are basically conducted based on commonly used inventory. As shown in Figure 10, the 3D CAD design file for the automation machine includes data on the BOM and the 3D shape. \begin{table}
\begin{tabular}{c c} \hline \hline
**Classification** & **Rendering Server** \\ \hline Operating system & Windows 10 Pro \\ Specification & AMD Ryzen 9 3900X, Mem 64 GB, SSD 4 TB \\ Purpose & 3D model rendering and streaming \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Implementation of Rendering Server. Figure 9: Automated facilities of Company T’s. The implemented VR engineering process was implemented in a total of four projects as shown in Figure 11. FBXexport wraps it and delivers it in DLL format to use FBX-related API in Unity3D project. CAD Convertor creates and displays a mesh on the screen based on DLLs such as CAD and FBX, and delivers it to the cloud server. VR Application uses libaray such as AR Core, Intelloid, and WebRTC to build a platform in AR environment and deliver it to users. The VR Projects Parser uses VB.net to transmit a program written through an actual Inventor to CAD Convertor through socket communication. The reason why it is written in VB.net is that the API provided by Inventor is provided through VB.net, and it is transmitted as a loopback for sharing between processes. A CAD Converter is a necessary tool for converting these 3D CAD design files into 3D objects in a VR environment. The CAD Converter role is performed by the VR Parser developed in this study. The.iam file should be loaded as shown in Figure 12 to read the information in the CAD file. When all are loaded, BOM and 3D objects are created. By implementing the BOM data and metadata in CAD design files as the Address Space of CPS, a VR Parser can transmit BOM data to an OPC UA-based CPS server. When the transmission is completed, the OPC UA client program can access the CPS server to verify that the structure of the BOM data is created in the Address Space. Further, when accessing the CPS server, it can be confirmed that the structure of the BOM data is generated as shown in the figure. As shown in Figure 13, the BOM structure of the CAD file was typically generated as the Address Space in CPS, and the entire part information and the operable part information were implemented in the Address Space. Figure 11: VR engineering project configuration. Figure 10: iam Design File with Inventor. To optimize the FBX model file capacity, the CAD converter can extract 3D objects as FBX models.