## 2 Related Works
Subsequently, studies that implement DTs in conjunction with AR or VR applied in the industry were reviewed to establish the architectures and technologies used by the authors in [26], who propose an AR-based DT method for the compatibility verification of building information modeling (BIM) data applied in semiconductor manufacturing (FAB). The system was implemented in Unity-based AR/visual SLAM along with AR Foundation using SLAM, 2D tracking, and local anchoring API in ARCore. The results showed that the implemented system allows for precise adjustment of the AR model and the real object through AR tracking and anchoring technology, improving the compatibility of objects. In [27], they develop DT in industrial environments, with AR and VR emphasizing the incorporation of other technologies such as system integration, connectivity with industrial protocols, and cloud services to enhance the capabilities of the digital environment. They use the Unity platform as a real-time 3D development tool due to its cross-platform capacity, and for system integration, they use Node-RED and the MQTT protocol. The results showed that the proposed DT provides a more complete understanding of the modeled process, with real-time interaction and dynamic visualization allowing for improved decision-making. In [28], they implemented a DT for the control and monitoring of a process with AR; the system was implemented in a modular production station MPS 500. The architecture consists of a PLC and a Raspberry Pi for sending process data to the cloud using Modbus TCP/IP and the M2M protocol; subsequently, the data are sent from the RPI to Unity for the development of the DT application for visualization and control via AR. The results showed that robust industrial protocols can be used for communication in interaction with AR, in addition to producing a DT with a user-friendly interface. In [29], they present the design and implementation of an AR-based assembly line for Industry 4.0 applications. For the design, they used Unity to create an interactive and easy-to-use AR application for training, and it was implemented in Festo's MPS-PA. Among the technologies that stand out is computer vision, and a scanner was used to produce a 3D design, and it was later exported to Solid Works. The results highlighted the potential of AR technology for assembly line operations, improving assembly line operations, productivity, and training. Finally, works were reviewed at the simulation level where the results obtained show the feasibility of improving the processes and can also be implemented in the industry. In [30], they propose an architecture to promote a reconfigurable manufacturing system (RMS) through a DT, where it is proposed to create an integrated platform for simulation and monitoring. In addition, they analyze how the CPS-MES architecture serves the evolution of the RMS; to validate the proposal, they implement it in Unreal Engine 4 (UE4) software where the simulation of planned RMS configurations is carried out; the performance of the configurations is calculated planned, and they obtained the optimized configuration. In [31], they analyze the asset administration shell (AAS) in terms of structure, components, sub-models, and communication protocols, such as OPC UA and MQTT, or interfaces that allow vertical and horizontal communication. The virtual production test bench and its implementation are carried out at the simulation level by creating a virtual factory where the tests are carried out, and it was observed that it considerably reduces time and uses relevant standards defined by the user, such as the names and attributes of the parameters. In [32], they propose the realization of a DT based on the DT definition language for data exchange with any application that complies with the open platform unified communications architecture; they use OPC UA to structure in DT definition language (DTDL). The implementation of the model was carried out at the simulation level.