## 4 Experimental Results
### User Evaluation  
User acceptance is critical for assessing usability of QDARV development tools. Therefore, user evaluation was conducted in this study. The participants were 10 graduate students majoring in mechanical engineering. They were divided into two groups according to their research backgrounds, researcher groups and operator groups. Among them, researchers have a certain programming foundation or AR technology knowledge, while the operators do not understand programming and AR technology. This study adopted heuristic evaluation [44; 45] technology to evaluate users of QDARV development tools, which uses user satisfaction surveys to analyze the usability of the system. Table 2 shows the evaluation questionnaire of QDARV development tool, which was used to obtain the feedback of participants.  
The participants used the QDARV tool to perform AR registration based on QR code and AR registration based on SLAM map reloading, respectively. In order to verify the effectiveness and quality of the proposed development tools, qualitative and quantitative usability studies were conducted, and participants were asked to perform specific tasks as shown in Tables 3 and 4.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**NO.** & **Tasks** \\ \hline
1 & Record a video of the scene and save it as an image sequence \\ \hline
2 & Build scene SLAM maps and place virtual models \\ \hline
3 & Control the rotation, zoom and translation of the 3D models through keyboard or mouse interaction \\ \hline
4 & Save SLAM map and SLAM-AR display content script file \\ \hline
5 & Scan the scene of the established map and implement the reloading of the virtual models \\ \hline \hline \end{tabular}
\end{table}
Table 4: AR registration task based on SLAM map reloading.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Question Number** & **Question** \\ \hline Q1 & The current status of the system is visualized \\ \hline Q2 & The system has a logical and comprehensible command structure \\ \hline Q3 & The system can be operated without much professional experience \\ \hline Q4 & The system has a consistent, standardized structure \\ \hline Q5 & Users can easily find and fix errors \\ \hline Q6 & The system minimizes the user’s memory load by making objects, actions, and options visible \\ \hline Q7 & The system operation is efficient and flexible for the user \\ \hline Q8 & The system interface is aesthetic and minimalist without extraneous information \\ \hline Q9 & The system can help users identify and diagnose errors \\ \hline Q10 & The system provides help to facilitate understanding of the functions presented \\ \hline \hline \end{tabular}
\end{table}
Table 2: Evaluation questionnaire of QDARV development tool.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**NO.** & **Tasks** \\ \hline
1 & Select QR code ID \\ \hline
2 & Import assembly or instrument file \\ \hline
3 & Configure assembly disassembly animation or instrument description content \\ \hline
4 & Save disassembly animation script file or instrument display script file \\ \hline
5 & Scan the QR code to superimpose the disassembly animation or industrial instrument, and realize the animation demonstration \\ \hline \hline \end{tabular}
\end{table}
Table 3: AR registration task based on QR code.  
There were five possible answers: very dissatisfied (2 points), dissatisfied (4 points), ordinary system (6 points), satisfied (8 points), and very satisfied (10 points). According to these options, Table 5 shows the user evaluation results of the QDARV development tool. Overall, QDARV received positive feedback from participants. Participants noted that the functions designed in the toolkit are easy to understand, useful for beginners who do not know programming but want to develop AR applications, and the entire development process is efficient and flexible. Participants also provided some feedback needed to be improved, such as the design of the interface can be clearer, and hints and fixes should be given when operation errors occur.