## 5 Conclusions  
In this paper, we proposed a VR/AR collaboration model and VR engineering process using CPS applied with international standard technology. Using VR/AR rendering of product design 3D drawings in the manufacturing industry, a collaborative model was presented to allow participants to participate in design at the same time, and an application was developed to check the virtualization model with data collected through OPC UA-based CPS. The programs used in machine design and product design currently use 100% foreign software. However, the current foreign software is specialized in design, but collaborative design does not provide functionality, so the actual design process of reviewing and reflecting opinions, and then simulating them, can be replaced with domestic programs to cover the growth of foreign design programs. Further, domestic manufacturers will find problems later by starting products or main production after design is completed, and it will take a long time and high cost due to the method of re-reflecting and re-production. However, sufficient simulation and design review using the product inspection system can dramatically reduce this time and cost, thus contributing to the competitiveness of manufacturing companies and actively using it for smart factories in the manufacturing industry.  
In this study, we developed a converter that converts design CAD files and BOMs into graphic models and CPS models, and that successfully loads BOM data of 3D CAD files from the VR Parser and sends BOM data to CPS server to construct Address Space. We also successfully extracted 3D objects converted from CAD files with capacity-optimized FBX. A CPS server, a middleware operating under the OPC UA protocol, was established to link OPC UA-BOM Address Space with OPC UA-BOM-based real-time values. In addition, when converting to 3D VR content using CAD drawings, it was implemented in the same way as the measured equipment, and errors were determined in CPS through the calculated load value of the load in the physical engine as the value generated by the simulator.  
Here, time and competency were both insufficient to implement all of the proposed VR/AR collaboration models. In the future, we will develop a VR/AR collaborative design client to create virtual characters for multi-user access, VR and motion capture wearers, and build a WebRTC-based backend (server and service) to stream high-end content and voice communication between users using VoIP.  
Conceptualization, J.K.; methodology, J.K.; validation, J.K. and J.J.; formal analysis J.K.; investigation, J.K.; resources, J.K.; data curation, J.K.; writing--original draft preparation, J.K.; writing--review and editing, J.K.; supervision, J.J.; project administration, J.K.; funding acquisition, J.J. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center) support program (IITP-2022-2018-0-01417) supervised by the IITP (Institute for Information & Communications Technology Planning & Evaluation). Also, this work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1F1A1060054).  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Classification** & **Measurement Location** & **Frames per Second** & **Resolution** \\ \hline
1 & Full view from parent & 86 & 2K (\(2048\times 1080\)) \\
2 & Full foreground from left end & 88 & 2K (\(2048\times 1080\)) \\
3 & Full foreground from right end & 83 & 2K (\(2048\times 1080\)) \\ \hline Average Number of & & & \\ Frames per Second & - & 85.6 & 2K (\(2048\times 1080\)) \\ \hline \hline \end{tabular}
\end{table}
Table 6: Frame count and resolution per second.