# Towards the Evaluation of Augmented Reality in the Metaverse: Information Presentation Modes
## 3 The Desktop-Simulated Testing Environment (DSTE)
### DSTE Description  
**Implementation. ** We developed the DSTE on Unity 3D Engine. LEGO 3D CAD models were imported in Unity 3D, while all of the simulated AR information needed to be modeled in the software environment. Unity 3D is used to create the virtual scenes and set all experimental parameters (editor mode). Considering that no resolution limitation has been imposed on users' computer screens, in Unity, the GUI Canvas Scaler was set in \"Scale with screen size\" mode to ensure the correct anchoring of the GUI buttons. Then, the proposed DSTE is built into an executable file, which needs to be sent to the participants (build mode). It was successfully tested with Windows and macOS operating systems. During the experiment, the application acquires and stores (in a simple ASCII text file) the time data for each testing condition. The output file is then sent back to the experimenters. **GUI buttons. ** During the experiment, users are asked to click a button to start. Then, they can execute the assembly task, selecting and placing the assigned LEGO pieces. When they place a LEGO brick, they can continue with the following step by clicking a button (right arrow in Figure 2) in the GUI. Users can also move to the previous step in case  
Figure 5: Assembling and disassembling metaphors: (**a**) the picked blue LEGO brick is attached to the placed red brick in a way different from that required by the instruction; (**b**) an “undo” button allows the user to delete the last blue LEGO brick that they wrongly placed; (**c**) the brick that needs to be disassembled is instantly removed after clicking on the “undo” button. Figure 6: Slider used to change the camera point of view: (**a**) default camera orientation, (**b**) left rotation of the camera point of view, and (**c**) right rotation of the camera point of view. of a mistake through another button (left arrow in Figure 2). The completion time is measured for each trial. It is automatically stored in the output ASCII text file. If users are disturbed during the trial, they can move away from their computer and come back by clicking a button to restart that trial (\"reset\" button in Figure 2). All of these buttons are in the bottom-right corner of the GUI. In this current version of the DSTE, errors are not automatically detected. Thus, if experimenters need this information, they must either watch the recordings of the experiment or follow the users while doing it and manually annotate errors. **Dual-task exercise. ** The DSTE can assess the mental workload in the assembly task using a dual-task paradigm, inspired by [PERSON]'s work [42]. At various time intervals, users receive a signal in the form of the color change of a letter placed at the top center of the interface (letter \"A\" in Figure 2). They have to quickly respond to this signal by pushing the \"S\" key on the keyboard. After this action, the color of the letter reverses again, and the software records and stores the reaction time in the ASCII output file. Then, after a time interval that can randomly range from 8 s to 18 s, there is another signal, and so on. In the editing phase, the test designer can change the time interval within which users have to respond to the dual-task exercise. **Training scene. ** We inserted a training scene in the testing environment to help users become familiar with all possible interactions. When users start the training, a popup window is displayed. It contains short text, images, and videos explaining how users should interact with the application. It can also be recalled during the execution of the experiment through a GUI button (question mark in Figure 2). During the training, they can build abstract shapes following (or not) the instructions provided. The verification of the training progress is left to users or, if present, to the experimenter who follows users remotely. **Assembly trials. ** After the training, users start the assembly trials for the experiment.