## 4 Conceptual Framework for Augmented Reality Application
### Digital Twin  
After completing the stages of data collection, geometric model development, process model construction, and evaluating the effectiveness of representing these approaches, it is time to integrate these two tools to create a digital twin in an augmented-reality-enhanced environment. This process is conceptually illustrated in the flowchart presented in Figure 11.  
As previously mentioned, the digital twin of an industrial process represents, virtually and in real time, a physical system or process in the digital environment. By collecting and integrating data from sensors and other sources, this digital model faithfully mirrors the characteristics and behaviors of the real-world object, enabling precise monitoring, simulation, and optimization of its performance. With valuable insights provided by the digital twin, decisions are made in an informed and strategic manner, while virtual tests allow the identification of potential improvements and anticipation of issues in the physical world [75; 76; 77]. The digital twin of augmented reality goes beyond a mere virtual representation of the industrial process. Its true strength lies in the continuous real-time integration with the physical system, making it a faithful and dynamic copy of the real process, instantly reflecting any change, update, or relevant event [78; 79]. Through this continuous integration, the digital twin receives real-time data from sensors, equipment, and other sources, ensuring that its virtual model remains synchronized with the ever-evolving reality of the industrial process. This approach provides an accurate and up-to-date view of the system at hand [80; 81]. Furthermore, the close relationship between the digital twin and the industrial process allows for applying advanced techniques such as artificial intelligence and machine learning. With the continuous flow of real-time data, the digital twin learns from the behavior of the physical system and enhances its predictions and analyses, generating even more value and insights for the operation [82; 83]. The digital twin offers several advantages to the process, one of them being its ability to anticipate the performance of the product or system, identifying and predicting potential issues, which guides towards proper optimization. This approach significantly advances the accuracy and efficiency of material selection used in the product [84] and enables detailed monitoring of the evolution of dynamic parameters. The innovative methodology based on digital twins enables this optimization by combining static analyses with dynamic executions [85]. The digital twin plays a crucial role in this process, allowing the monitoring of the design stages' history and tracking improvements over time, ensuring a highly effective iterative optimization. By refining the focus on iterative optimization, we attain a high-level design, incorporating continuous improvements in the product's conception, from its initial phase to the finest detail [86]. This approach goes beyond the limitations of traditional simulations, which often overlook crucial aspects of project success. With the assistance of digital twins, it becomes possible to thoroughly explore the complex interactions of the system, identify areas for improvement, and make informed decisions at every stage of the design process. This results in more robust, efficient products that align with market and customer expectations [87]. Integrating digital twins with augmented reality is a powerful combination that allows for a comprehensive and in-depth evaluation of the industrial process and the physical structure of equipment from various perspectives. This synergy between the technologies provides a new level of interactivity and immersion, empowering operators and engineers to explore the process's and equipment's vital details in real time. This makes decision making more informed and proactive, enabling agile problem solving and continuous improvement of industrial processes [83].