Evaluation of Virtual Reality Application in Construction Teaching: A Comparative Study of Undergraduates

Abstract

Construction courses are characterized by a combination of theoretical and practical knowledge; however, the teaching of practical knowledge is often absent due to safety and cost considerations. VR can improve the teaching of practical knowledge by facilitating interactions between teachers and students through virtual means, regardless of location, which is a weakness of current lecture-based teaching, especially in the COVID-19 era. Therefore, this paper aims to evaluate the effect and discuss the prospect of VR in construction teaching, with a comparative study of 50 students who were evenly divided into two groups and taught using traditional teaching and VR teaching, respectively. This experiment shows that VR teaching improves the students’ learning enthusiasm and satisfaction, especially in terms of practical knowledge. Additionally, students believe the combination of traditional and VR teachings can be more helpful in construction teaching. The findings of this research strengthened the advantages of VR in delivering practical knowledge in construction teaching.

1. Introduction

Virtual reality (VR) is a model of reality created by technical means, the objects and subjects of which are perceived by humans through their sensations: sight, hearing, smell, and touch [1]. It is characterized by immersion, interactivity and constructiveness [2]. VR’s multiperception brings multiple sensory inputs into the whole learning scene, improves learning immersion in dynamic human–computer interactions [2], stimulates learning interest and positive emotions [3], and increases the creative and self-learning ability of students [4].

Virtual simulation teaching is an important tool for modern education and will lead to the reform of traditional teaching and improve the quality of talent training [5]. Notably, various researches show that VR has a positive effect on teaching in education fields [6], and it can direct interactions between teachers and students through virtual means, regardless of location [7]. VR enhances collaboration in the classroom and promotes a meaningful use of technology in the science classroom, which provides disciplinary convergence through underlying cognitive attributes, affective factors and skills implementation [8]. VR is also believed to benefit from positive factors such as novelty, embodiment and further motivational effects [9]. Another advantage of VR is the positive impact on learning success when bodily movements are included in the learning process [10]. Brill and Galloway [11] expressed that teaching technology has a positive impact on their teaching and student learning, and believe classroom technology can improve students’ learning, participation and attention. As of now, VR teaching has been applied in various fields of education and teaching, such as chemistry [12], medicine [13] and mathematics [14]. Studies have shown that students’ motivation, interactivity and adaptability improved to varying degrees at the end of a VR-assisted course [15]. In the post COVID-19 era, virtual world technology is seen as advantageous and suitable for the requirements of higher education [16].

Construction courses are unique in nature, as they are closely combined with practice and theory. In most civil engineering curriculums, an additional construction practice course is needed to further master the content of construction course. At the present stage, traditional teaching adopts direct lecture-based and picture-assisted explanation methods, and most of the “teaching” takes place within the confines of the classroom [17]. Ideally, the construction teaching should enable students to grasp the complexities of the construction process and the physical principles behind it [18]. Construction sites are dynamic, where problems can arise at any time. Therefore, students should acquire predictive as well as problem-solving skills, which can be challenging for them since accomplishing these objectives in the classroom requires a high level of spatial imagination and conceptualization skills. On top of this, the construction process is often complex, containing different techniques and defined construction sequences, which can be difficult to remember. While practical experience on site can be an effective solution to this problem [19], it is not always implementable or effective for safety and convenience reasons [20].

The rapid development of VR technology is an avenue that can provide new possibilities for practical knowledge of both construction industry and construction teaching. In the beginning, VR was mainly used by architectural firms to visualize building and infrastructure designs during the concept or prototype development phase of a project [21]. The construction industry has also adopted VR to improve safety awareness [22]. In civil engineering practice, VR has been found to hold great promise for the training of construction workers [23]. In addition, participants engaged in design review tasks were perceived to have higher cognitive load and perform better in the VR environment [24]. VR can realize the virtualization of the teaching environment and improve communications in the professional workplace and other shared spaces [25], which allows students to experience in a virtual environment close to the actual construction site. In the teaching of bridge construction [26], construction of earthquake-resistant buildings [27], complex 3D layouts in structural engineering [28] and infrastructure management [18], studies showed that students were able to use VR to better understand concepts, interact with models more confidently, and grasp teacher guidance more easily.

Although past studies have identified many benefits and the potential of VR in construction teaching, they have mostly been limited to students’ perceptions of the built environment and models, and lacked hands-on simulations in which students directly participated in simulated construction. In addition, the evaluation of VR teaching is mostly immediate qualitative interviews, lacking systematic comparative and quantitative analysis. Therefore, the primary objective of this paper is to explore the feasibility and advantages of VR in construction teaching, so as to improve the learning effect and interest of students. In particular, we selected laying waterproof rolls using the hot-melt method as the course content, and students used VR devices to complete the process. On that basis, this paper evaluates the effect of VR in construction teaching among 50 junior students in China, including whether VR teaching can enhance the theoretical and practical knowledge memory and whether VR teaching can reduce the cognitive load of the students as well as the satisfaction of virtual reality teaching. Through the self-developed coiled waterproof roofing VR model shared on the official website of South China University of Technology [29], the comparative experiment between VR teaching and traditional teaching was conducted to analyze the unique advantages of VR teaching.

2. Materials and Methods

2.1. Development of the VR Model

2.1.1. Platform and Devices

Firstly, we have chosen the process of laying waterproof rolls as the modelling content, which takes into account the teaching schedule and the characteristics of the waterproof laying itself. The laying of waterproof rolls aims to ensure that the roof does not leak, which is carried out after the main structure has been constructed, with strong practicality and interactivity. At the same time, the flame used in the hot-melt method can be a safety hazard, so simulating this construction process also emphasizes the importance of construction safety and allows students to avoid risks in a virtual environment.

The VR model is developed using Unity3D platform, a cross-platform game engine that integrates graphics, audio, physics, human–computer interaction and web technologies. While the graphics rendering and realism are not considered superior, it is very extensible and supports VR development in Visual C# and JavaScript. C# is the primary game scripting language for the Unity3D engine, and its use can greatly improve development efficiency, so this simulation was developed using the C# programming language. The VR device used in this study is the HTC Vive, which comes with two controllers, left and right, in addition to the regular VR headset to facilitate an operational and interactive simulation, as shown in Figure 1.

2.1.2. 3D Modeling

We choose the mesh approach with Blender and Revit software for 3D modeling, which does not have a specific formula, but simply generates two-dimensional surfaces for a number of points and has a more flexible solution for the optimization of computer graphics processing. Additionally, mesh modeling is a modeling method for establishing a physical model by describing the various flat or curved surfaces of a entity, which is achieved by obtaining the feature points that make up the model and then generating a mesh of the corresponding points according to certain rules, with each mesh consisting of three vertices. Finally, the meshes are joined together to form the final model.

Blender comes with a file that can be imported natively into Unity3D, allowing developers to modify models in real time. Revit supports the import of CAD drawings and generates a range of architectural elements, and its exported files can be imported into Blender and Unity3D. As shown in Figure 2, a flamethrower model is built in Blender according to its actual size. After the model has been successfully imported into Unity and placed into the proper scene as designed, the simulation requires a number of effects such as model animations, particle animations and sound to enhance the presentation of the simulation. With particle animation, Unity3D can achieve effects such as flames, smoke and fluids, which are necessary for the hot-melt method.

2.1.3. User Interface Design

In traditional user interface (UI) design in Unity, the elements are overlaid, and the fonts are relatively clear to the user; however, the helmet can cause the fonts to not display properly in the overlay mode. Therefore, the UI of this simulation system is built through Unity’s own UGUI; through UGUI, developers can modify the effect in real time, automatically generate the atlas and help UI object positioning. Moreover, camera mode is adopted as the rendering mode of the Canvas, which means that UI elements in the model are kept at a certain distance from the camera (i.e., the user), so that the UI always floats in the user’s field of view, and the position of its UI elements maintains a certain geometric relationship with the player’s position. After determining the placement and rendering mode, it is necessary to create the Canvas, then add components under the Canvas and finally create basic elements, such as Button and Text. It is advisable to create elements named and categorized according to their specific function to facilitate animation editing and code control. Notably, it is often necessary to create one or more empty objects within the scene, which can be mounted to control the code, thus helping the developer to better manage the code and maintain the UI. Consequently, Revit and special effects in Unity3D allow users to immerse themselves in the VR interface and distinguish building elements, construction tools and flames clearly. The interface of the VR model is shown in Figure 3.

The VR system is built considering the knowledge required for the process and resources available. For content with strong textual narrative, such as the construction sequence, text and sound are used to display; for content requiring hands-on experience, such as the practical simulation part of the hot gluing method, a hands-on approach is provided to enhance the students’ impression. The model focuses on learning abstract knowledge and developing practical skills.

2.2. Conduct of Comparative Experiments

2.2.1. Division of Comparison Groups

According to the teaching status quo and goals, the aim of this experiment was to explore the memory effects and cognitive load of VR teaching versus traditional teaching at the South China University of Technology (SCUT). SCUT is a representative engineering higher-education institution in China, comprising a significant proportion of civil engineering students in southern China. Each year, a total of around 105 junior students in at the university were required to take the construction course. It is understood that none of these students have had access to or used VR devices before, nor have they been involved in practical training or visits related to coiled waterproof roofing and therefore will not be affected by the relevant experience in assessing learning outcomes. To improve the efficiency of the experiment, the participants were randomly selected using a random sample of 50 out of 105 students. The 50 selected participants were then divided randomly and equally into two groups: VR teaching as the experimental group and traditional teaching as the control group. Before the start of the experiment, the participants were given a brief ten-minute intensive training session by the developer of the program to ensure that each student had the same level of understanding of the basic operation of the VR devices.

With students wearing VR headsets, guided by text and sound prompts, and holding the controllers in their hands to move and manipulate tools, the VR teaching is carried out, and the following three teaching tasks are completed: learning how to treat the base and apply the base agent, learning the requirements for treating special areas and knowing the hot-melt process. In order to provide a better understanding of our VR model, we have provided the VR program public download site for readers’ reference [29].

Traditional teaching in China can be introduced in three stages: before the class, students read the textbook to preview the knowledge they will learn; during class, the teacher uses multimedia, such as slides and videos, to explain the knowledge to students, who refer to the textbook, receive lectures from the teacher, and mark key points of knowledge; after class, students complete their homework and take the initiative to ask the teacher for advice if they have doubts. Specifically, the civil engineering construction course is highly practical, covering a wide range of construction techniques, technologies, machinery and other related content. The textbook usually uses textual descriptions combined with pictures and diagrams to show the content, while the teacher adds pictures and videos from the construction site in addition to the textbook to give students a more realistic and concrete explanation of the course content. Although the main topic of the course is various construction techniques, the course is still basically taught with textbook. Traditional teaching allows for real-time interaction between teachers and students, with students’ questions being answered quickly by the teacher and being able to refer back to the textbook at any time, but the process lacks student’s immersive experiences of construction practice.

2.2.2. Implementation of the Experiment

Immediate and delayed examinations were conducted to evaluate the effects of immediate memory and delayed memory. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) cognitive load scale and teaching satisfaction evaluation were used to evaluate the experience. The NASA-TLX is a widely used subjective multidimensional assessment tool. The NASA-TLX scale includes six indicators of physical exertion, brain power consumption, teaching rhythm, performance satisfaction, degree of effort and frustration. Finally, a satisfaction test and interview was conducted with the experimenter to directly obtain the ideas of VR teaching stakeholders and to evaluate the application effect of VR in construction teaching. This study refers to the moderately difficult waterproof engineering teaching content and selects the theoretical and practical knowledge of coiled waterproof roofing as a teaching case.

Through group comparison experiments, questionnaires and interviews were conducted again to analyze the impact of virtual reality teaching on immediate and delayed memory effects, along with the cognitive load and experience of students in the teaching process.

Table 1. Comprehensive list of research methods.

Evaluation Content		Evaluation Method	Evaluation Index
Evaluation of memory effect	(1a) Immediate memory effect evaluation	Questionnaire test	1.The process steps of using the hot-melt method for the construction of laying waterproof rolls, the direction of the overlapping direction of the coil, the angle and other memories of the process principle and sequence. 2.The student’s observation of the construction details with the worker’s helmet. 3.The students’ ability to understand pictures under different teaching methods.
	(2a) Delayed memory effect evaluation	Questionnaire test
	(3a) Memory effect accuracy assessment	Questionnaire test
Cognitive experience assessment	(1b) Single cognitive load index comparison	Satisfaction test (NASA-TLX)	The pressure caused by brain power consumption, physical exertion, teaching rhythm, the satisfaction of performance, effort and the frustration in the teaching task.
	(2b) Proportion of single load index	Satisfaction test (NASA-TLX)
	(3b) NASA-TLX scale accuracy assessment	Satisfaction test (NASA-TLX)
Teaching satisfaction evaluation	(1c) Teaching satisfaction accuracy assessment	Satisfaction test	Knowledge-mastering effect, improving learning enthusiasm, hands-on ability, self-learning ability, analyzing and problem-solving skills, communication and cooperation ability, overall evaluation of teaching satisfaction.
	(2c) Post experiment interview feedback	Interview	The sensory experience, learning effects, restriction interference and the application scope of VR teaching in the VR teaching process.

shows the questions explored in this paper.

After the traditional teaching and VR teaching, the two groups of students were asked to complete the questionnaire test within 10 min. The questionnaire test has a setup of 10 questions, including seven single-choice questions and three fill-in-the-blank questions, each of which is 1 point. The first six questions refer to the process steps of using the hot-melt method for the construction of coiled waterproof roofing, the direction of the overlapping direction of the coil, the angle and other memories of the process principle and sequence. The seventh question examines the student’s observation of the construction details with the worker’s helmet. The last three questions are based on the hot-melt method of laying of waterproof rolls to explore the differences in the students’ ability to understand pictures under different teaching methods. According to the famous Ebbinghaus Forgetting Curve [30], after the learner’s brain receives new things, the speed of forgetting gradually changing from fast to slow. After more than 2 days, the memory retention rate of the original new things will be less than 30%. To explore the difference in the effect of the two teaching methods on delayed learning, the 50 students were given a questionnaire again two days after the initial experiment with the same test content as the initial experiment.

The cognitive experience assessment aims to explore whether the introduction of emerging technology equipment in construction teaching will interfere with the student learning experience and whether it can bring a more positive learning experience. After the completion of the initial experimental teaching task, both groups of students will have a satisfaction questionnaire survey on learning cognitive experience. The satisfaction questionnaire about learning experience uses the NASA-TLX to evaluate the load experience brought by the two teaching methods. The NASA-TLX experiment immediately collected the cognitive load level of the two groups on the six indicators after the initial experiment. The index of each indicator in the NASA-TLX scale ranges from 0 to 20 points, and every 2 points is divided into one class unit. A score of 0 indicates that the indicator load is extremely low, and a score of 20 indicates that the indicator load is extremely high.

Teaching satisfaction evaluation is he students’ evaluation of the course after education. First of all, the two groups of students evaluated the corresponding teaching methods by questionnaire survey after the subjective scoring of various cognitive load indicators. Based on the research purpose, to make the analysis more objective and scientific and to report the feedback of the teaching satisfaction evaluation table in the research question “whether the virtual reality technology will interfere with the overall learning experience of the students”, this study conducts an independent sample with a 95% confidence percentage. The t-test was used to determine the statistical significance of the experimental group memory in the evaluation of teaching satisfaction.

3. Results and Discussion

3.1. Reliability and Validity Tests

The paper questionnaires were distributed in the classroom, completed by the participants and collected on the spot. The same number of questionnaires were distributed as were collected, and all were considered valid.

Reliability and validity are the basic indicators of a questionnaire survey. Reliability refers to the internal stability and consistency of the questionnaire; validity is used to determine whether the results obtained from the questionnaire are true and valid and whether they accurately represent the level of functional needs being evaluated. The questionnaire reliability and validity statistics were conducted using SPSS 22.0 software, using the two indicators of KMO value and Bartlett’s sphericity test value. As shown in

Table 2. Reliability and validity analysis.

Cronbach’s Alpha	KMO Value	Bartlett’s Sphericity Test Sig Value
0.712	0.775	0.000

, Cronbach’s Alpha is between 0.7 and 0.8 with good reliability, the KMO value is between 0.7 and 0.8 and Bartlett’s sphericity test corresponds to a p value < 0.05, indicating that the results in this questionnaire are suitable for analysis.

3.2. Evaluation of Memory Effect

3.2.1. Immediate Memory Effect Evaluation

According to the test results, the experiment divides the different scores into “excellent” (9~10 points), “good” (6~8 points), “qualified” (3~5 points) and “unqualified” (1~2 points). The average score of the control group was higher than that of the experimental group by 18%. The data compilation showed that the hierarchical structure of the control group was better than the experimental group, as shown in Figure 4a.

The performance of each group of students in various types of questions is different, as shown in Figure 4b. In the first six questions related to the construction principle of coiled waterproof roofing, the control group scored twice as much as the experimental group. There is no significant difference in the scores between the two groups of the seventh question about construction safety details and the eighth and ninth questions on construction structure. In the map recognition questions involving specific process operation, the experimental group were 96% correct, and the scoring rate was twice that of the control group. Therefore, we can learn from the students’ feedback compared with the traditional teaching method that VR teaching has no obvious advantage for the mastery of theoretical knowledge in instantaneous memory, but VR teaching is more effective when it involves process practice memory.

3.2.2. Delayed Memory Effect Evaluation

From the overall questionnaire test results, the average scores of the control group and the experimental group after 2 days of teaching were lower than the immediate test after teaching, and the difference between the two groups was similar to the immediate test. The average score of the control group was higher than that of the experimental group by 14%. In the four grades of achievement, due to the forgotten knowledge points, the experimental group with no advantage in test results was at the “qualified” level and below after 2 days, while the control group hierarchy was slightly better than the experimental group, as shown in Figure 5a. Therefore, preliminary analysis shows that VR teaching does not have much impact on the retention of newly acquired knowledge after a period of time.

In delayed memory, the scoring rate of each type of students in the two groups is basically the same as the immediate test, as shown in Figure 5b. In the first six questions concerning the construction principle of the coiled waterproof roofing, the control group scored twice as much as the experimental group. In the identification questions involving specific process operations, the control group has forgotten the teaching content, but the experimental group is still more than 90% accuracy in the whole group. In the seventh question of construction safety details and the eighth and ninth questions on construction structure, there is no significant difference in the scores between the two groups. Therefore, compared with the traditional teaching methods, VR teaching has no obvious advantages for the delayed mastery of theoretical knowledge, but it is more beneficial to the delayed mastery of specific-process practice memory.

3.2.3. Memory Effect Accuracy Assessment

According to the research question “whether VR can enhance the instant knowledge memory effect compared with the traditional teaching method”, when 95% is the percentage of confidence interval (CI) is 95%, Sig = 0.142 (Sig ≥ 0.05), and the variance is homogeneous, then t(9) = −1.6, p = 0.117 (p ≥ 0.05), showing no significant difference. Therefore, compared with the traditional teaching method, VR is not effective in enhancing the effect of instant knowledge memory and knowledge mastery.

Correspondingly, in the evaluation of whether VR enhances the effect of delayed knowledge memory, when CI = 95%, Sig = 0.134 (Sig ≥ 0.05), and the variance is homogeneous, then t(9) = −1.309, p = 0.197 (p ≥ 0.05), and thus the results showed no significant difference. Consequently, VR technology is not effective in enhancing students’ delayed memory retention compared with the traditional teaching.

However, when the students’ performance in the specific process practice memories were analyzed separately, the two groups showed a certain degree of difference. From the point of view of immediate memory evaluation, 95% is the percentage of confidence interval (CI = 95%), Sig = 0.000 (Sig ≤ 0.05), and when the variance is not uniform, then t(9) = 2.711, p = 0.011 (p ≤ 0.05), and thus the effect is statistically significant. In the delayed memory evaluation performance, 95% is the percentage of confidence interval (CI = 95%), Sig = 0.000 (Sig ≤ 0.05), and when the variance is not uniform, then t(9) = 3.118, p = 0.004 (p ≤ 0.05), and thus the effect is statistically significant. Therefore, compared with traditional teaching methods, VR teaching is more effective in immediate and delayed mastery of specific process practice memories.

Combined with the previous analysis and summary, and compared with the traditional teaching method, VR teaching has no obvious advantages for the immediate and delayed mastery of theoretical knowledge, but it is more beneficial to the immediate and delayed mastery of the specific-process practice memories.

3.3. Cognitive Experience Assessment

3.3.1. Single Cognitive Load Index Comparison

Under the premise that the load indexes of the two groups are similar, the control group and the experimental group have less difference in the four factors of perceived brain power consumption, teaching rhythm, satisfaction with their performance and effort in the learning process. Alternatively, in the physical exertion and frustration load indicators, the difference is more than two load units, which is more significant. The cognitive load indexes of each group are shown in Figure 6.

The control group and the experimental group were similar in terms of brain power consumption, teaching rhythm, performance satisfaction and the degree of effort in the process, while the experimental group produced significantly higher physical exertion than the control group, and the analysis in the previous section shows that the teaching test overall effect of the control group was better than the experimental group, though the control group produced significantly more frustration than the experimental group. According to experimental observations, the experimental group students showed more enthusiasm of the VR teaching process. Although it was their first experience with VR teaching devices, they could independently grasp the teaching rhythm and participate in the process practice in the virtual world and show confidence and interest in the construction course. Therefore, even if the experimental group students produced a large amount of physical exertion due to the teaching, and there was no advantage in the subsequent knowledge point test, the pleasant teaching experience can enhance self-confidence and interest, and did not produce the frustration of the control group.

3.3.2. The Proportion of Single Load Index

This experiment considers the pressure brought by the brain power consumption, physical exertion, teaching rhythm, the satisfaction of performance, effort and the frustration in the teaching task as the total load. To explore the difference in the contribution of the single load index to those of the total load in the control group and the experimental group, the two groups of students were to sort the proportion of the above six load indicators to the total load in order and select the proportion of each group. The first two items with the largest proportion and the last two with the smallest proportion are statistically analyzed, as shown in Figure 7.

In the control group, the pressure brought by the teaching rhythm and the pressure brought by the mental power consumption became the two items with a larger total load. Simultaneously, no one chose the pressure caused by the teaching rhythm as the two items with the smallest load. The pressure of the teaching rhythm is indeed a load that cannot be ignored in traditional teaching. In the traditional teaching method, the teaching rhythm is almost completely in the hands of the teacher. The students need to follow the lecturer’s teaching and while simultaneously understanding and memorizing. No one chose the physical exertion index among the two largest proportions. Simultaneously, in the two load surveys with the smallest proportion, 50% of the answers think that the proportion of physical exertion is the smallest. Obviously, in the traditional teaching mode, students only need to sit still, which brings about the lack of experience and participation.

In the experimental group, the pressure brought by the teaching rhythm and the pressure generated to achieve the satisfaction of performance became the two items with the largest total load. The frustration index was clearly marked as the smallest of the two, while no one chose frustration in the two largest proportions. According to observation, in VR teaching, the teaching rhythm is freely controlled by the students, and the need for self-exploration is both challenging and expectable; however, when students are unfamiliar with the teaching cases and the operation of VR devices, students will be subconsciously nervous about the teaching rhythm and the operation performance.

Compared with traditional teaching, in VR teaching, students need to expend significant physical exertion, but self-exploration and participation can improve self-confidence and interest, thus reducing the frustration from the teaching. The grasping of the teaching rhythm should be noticed in both teaching methods. If the students’ autonomy is too large or too small, there will be a large load in the studying due to the teaching rhythm.

3.3.3. NASA-TLX Scale Accuracy Assessment

In the “physical power consumption” score of the NASA-TLX scale filled out by the two groups of students, where the percentage of confidence interval is 95% (CI = 95%), Sig = 0.321 (Sig ≥ 0.05), and the variance is homogeneous, then t (9) = 6.709, p = 0.000 (p ≤ 0.05), and thus the results showed significant differences. Therefore, compared with traditional teaching, in VR teaching, students need to expend significant physical exertion. In the “frustration” score of the NASA-TLX scale filled out by the two groups of students, where the percentage of confidence interval is 95% (CI = 95%), Sig = 0.620 (Sig ≥ 0.05), and the variance is homogeneous, then t (9) = −5.588, p = 0.000 (p ≤ 0.05), and thus the results showed significant differences. Therefore, compared with traditional teaching, in VR teaching, the students’ negative feelings, such as frustration, are significantly reduced. In summary, in terms of the overall learning experience, the use of VR technology will produce significant physical exertion, but negative emotions, such as frustration, can be significantly reduced.

3.4. Teaching Satisfaction Evaluation

The students’ satisfaction with the teaching methods in the ability training is divided into “very satisfied (10 points)”, “satisfied (8 points)”, “general (6 points)”, “relatively dissatisfied (4 points)” and “very dissatisfied (2 points)”. The content of the teaching-methods satisfaction survey includes “Knowledge mastering effect”, “Improving learning enthusiasm”, “Hands-on ability”, “Self-learning ability”, “Analyzing and problem-solving skills”, “Communication and cooperation ability” and “Overall evaluation of teaching satisfaction”. The results are shown in Figure 8.

From the evaluation of the overall evaluation of teaching effect, 20% of the students in the control group were “satisfied” with the traditional teaching method, 70% of the students thought that the teaching effect was “general”, and 10% of the students felt “less satisfied”. In the experimental group, 20% of the students felt “very satisfied” with VR teaching, 70% felt “satisfactory”, and the remaining 20% considered VR teaching to be “general.” From the perspective of hierarchical scores, the average satisfaction of the control group on the overall effect of teaching is at the “general” level, while that of the experimental group is higher than the level of “satisfied”. The experimental group gave higher satisfaction to the overall teaching effect.

In the process of achieving specific teaching objectives, students showed no significant difference in the satisfaction of the two methods in helping them master knowledge, or improve their self-learning, communication and cooperation ability. As was analyzed in the previous section, VR teaching has no obvious advantage in mastering the memory of theoretical knowledge. In terms of their self-learning ability, the reasons for the similar satisfaction of the two groups are different. According to the experimental observation and post experimental interviews, the control group believes that the self-learning ability through traditional teaching in the classroom is not enough for the students to master the knowledge and that it is necessary to self-study after class, thus indirectly cultivating the self-learning ability. The experimental group students believe that the students in VR teaching have complete autonomy and grasp the teaching rhythm in the virtual world, thus cultivating and training self-learning ability.

In terms of improving learning enthusiasm and cultivating hands-on practical ability, the experimental group was more satisfied than the control group who had traditional teaching, both of which were “relatively satisfied” and “very satisfied”. Through the use of VR devices, the experimental group students independently explored the construction teaching content, which has a strong sense of immersion and participation. This not only improves the enthusiasm for the construction course, but also enriches the practical ability in laying waterproof rolls.

3.4.1. Teaching Satisfaction Accuracy Assessment

In the scores of the “integrated teaching effect evaluation” of the teaching methods of the two groups of students, where 95% is the percentage of confidence interval (CI = 95%), Sig = 0.698 (Sig ≥ 0.05), and the variance is homogeneous, then t(9) = 3.666, p = 0.011 (p ≤ 0.05), and thus the results showed significant differences. Therefore, the experimental group’s satisfaction with the overall teaching effect of VR teaching was significantly better than that of the control group.

Among the various indicators of satisfaction evaluation, the students in the experimental group were more satisfied with the teaching objectives of “improving learning enthusiasm” and “cultivating hands-on practical ability” in VR teaching, and the evaluation of the satisfaction of the experimental group students on these two items was statistically significant. This study used an independent t-test. In the scores of the two groups of students’ satisfactions with the teaching method of “enhancing learning enthusiasm”, where 95% is the percentage of confidence interval (CI = 95%), Sig = 0.364 (Sig ≥ 0.05), and the variance is homogeneous, then t(9) = 8.610, p = 0.0000 (p ≤ 0.05), and thus the results showed significant differences.

In the scores of satisfactions between the two groups of students on the teaching method of “cultivating hands-on practical ability”, where 95% is the percentage of confidence interval (CI = 95%), Sig = 0.488 (Sig ≥ 0.05), and the variance is homogeneous, then t(9) =11.658, p = 0.0000 (p ≤0.05), and thus the results showed significant differences. Therefore, the satisfaction of the experimental group on VR teaching was significantly higher than that of the control group for the realization the goal of hands-on practical ability and the improvement of learning.

In summary, in terms of teaching satisfaction, the use of VR technology can improve students’ satisfaction with the overall teaching effect, especially in terms of “enhancing learning enthusiasm” and “cultivating hands-on practical ability”.

3.4.2. Post-Experiment Interview Feedback

Interviews were then conducted among 26 students who participated in the experiment, including 15 experimental group students, 10 control group students, and the developer of VR teaching models. Based on the practical experience, with the deepening of the interviews, the students expressed their opinions on the sensory experience, learning effects, restriction interference and the application scope of VR teaching in the VR teaching process.

The interview results show that in the sensory experience, the immersive experience of VR teaching can help to improve concentration, while the sensory stimulation of the theoretical text part in VR teaching is different due to individual differences but shows a larger interest in practical operation. In terms of improving the theoretical knowledge learning effect, VR teaching has no obvious advantages than traditional teaching. However, the improvement of the learning effect of practical skills play an indelible role in the formation and deepening of the cognition of courses and even the understanding of majors and industries. Additionally, students believe that VR teaching can provide an intuitive experience of construction techniques. In cognitive training, VR teaching can be used as supplementary training for construction site visits. Moreover, all students are optimistic and supportive of the application of more emerging VR technology that will be able to simulate more content in construction courses.

From the interviews with students, it is known that VR teaching alone would not significantly improve theoretical knowledge and that a combination of VR and traditional teaching would be a good option. Most students said that, although VR teaching can visually present theories, such as text and numerical values, due to the time pressure of mastering the pace of teaching and the inability to take notes in a fully immersive environment, the theoretical knowledge presented in VR teaching is like a “ fleeting cloud “ and can only be remembered instantly, which is a greater memory load than sitting still in a classroom. All students agreed that VR teaching should not replace traditional teaching, but should be used as a supplementary teaching tool to provide students with a visual experience of important construction processes after the teacher has delivered the classroom lectures. In terms of the frequency of VR use in classroom teaching, most students indicated that they could use VR devices for students to practice key processes in the form of exercises and lab sessions after teachers had completed their lectures.

In the view of developers, the research and development of a VR model for construction teaching require cross-knowledge of civil engineering and software development. Therefore, the time, manpower and cost of development of a VR model for construction teaching are higher, and the application of software and hardware devices have higher requirements. A VR model for construction teaching should also be tested and modified several times to achieve the best teaching results. Therefore, the development of a VR model for construction teaching is a momentous challenge.

According to the in-depth interview, compared with traditional teaching methods, the VR teaching effect is more optimistic regarding the process practice both in instant memory and delayed memory. Compared with traditional teaching methods, VR teaching can reduce negative emotions during the teaching process. The use of VR technology can improve students’ satisfaction with the overall teaching effect, especially in terms of “enhancing learning enthusiasm” and “cultivating hands-on practical ability”.

4. Conclusions and Future Work

This study develops a VR teaching model, which has been shared on the official website of South China University of Technology, and sets up a comparative experiment on traditional teaching and VR teaching to explore the application effect of VR in construction teaching. In the comparative experiment, the experimenter was first tested for immediate and delayed (2 days) memory effects, and then the cognitive load test was performed to evaluate the cognitive experience of the experimenter. Finally, the experimental participants and the VR teaching model developer were interviewed.

Based on the above experimental results we can learn that VR has a significant positive effect in increasing students’ enthusiasm for learning and developing hands-on practical skills, although unfamiliarity with operating the devices can make them nervous; however, VR teaching has no significant advantage in terms of immediate and delayed mastery of theoretical knowledge. Therefore, VR would be a good choice for courses with a strong practical requirement, such as, for example, physics labs, civil engineering materials labs, while for courses with a strong theoretical and memorization component, VR would be of very limited help. In conclusion, VR as a teaching tool can improve classroom outcomes but will not reverse or replace traditional teaching and learning.

VR in construction teaching has shown many advantages, but there are still many challenges and limitations that deserve our attention and research in future work.

(1)

In terms of sensory experience, the experiments used external headgear, mainly for visual and auditory purposes, to make students feel the teaching case; some students with myopia said that it caused a certain load on the eyes, and students had mixed feelings about the sensory stimulation in VR teaching due to personal differences;

(2)

VR teaching has a high dependence on high-cost software and hardware devices [31,32], which leads to the difficulties in developing a complete the VR teaching model. Additionally, the development of VR platforms requires certain skills, and it is vital to ensure the quality of the VR models in high resolution;

(3)

The use of the VR devices requires training and instruction and, in some cases, the devices are not sensitive enough to respond in time and requires repeated manipulation of the handle;

(4)

The VR devices used in the experiment have a certain range of spatial positioning, approximately within 4m × 3m, so students can only move within this range, which does not exactly match the range of the virtual space. Meanwhile, most students will rub against equipment such as lab tables and chairs, and are therefore limited in space when operating them.