Multi-user, Immersive Hot Air Balloon Simulation (iHABS) System

Research Objectives

The objectives of this research work are:

  • Build a multi-user, immersive hot air balloon simulation (iHABS) program based on educational theories of constructivism to study and evaluate the educational effectiveness of collaborative VR in learning.
  • Design and implement effective and usable VR Interaction Techniques to support the learning objectives of iHABS.

Short Description of iHABS

The iHABS system is an active experiential and exploratory learning environment developed using the immersive VR technology.  In iHABS, students can experience virtual hot air ballooning, and at the same time, learn the underlying physics principles constructively in a fun, engaging and collaborative setting.  They see this virtual world through a head-mounted display (HMD) that presents a stereoscopic view of the virtual world (Figure 1(a)).  They interact with the virtual world using a data glove (Figure 1(b)).  



Figure 1: VR devices used in iHABS (a) Head mounted display and (b) Cyberglove

Pedagogical Support: The pedagogical basis of this system is rooted in both the cognitive and social constructivism theory.  From the cognitive constructivism perspective, we have blended the experiential approach with guided-inquiry approach to make the learning experience more enriching and effective.  Social constructivism can take place formally, within the VE, and also informally, by encouraging the students to collaborate among themselves outside of the VE. 

Virtual World: The virtual world of iHABS is named “Paradise Island”.  It consists of the take off site and the landing site separated by high mountains.  This landscape design simulates the risk of hot air ballooning in a real-world situation and thus, imposes an implicit challenge to the students to land at an appropriate location.  Failing to land on an appropriate location, such as landing on the mountains or in the sea, may result in a serious “virtual” accident.  In iHABS, every student is represented as an avatar.  A snapshot of two avatars at iHABS take-off site is as shown in Figure 2 and a hot air balloon is shown in Figure 3

Figure 2: Two avatars at the balloon take-off site

Figure 3: A hot air balloon in the iHABS learning environment

Navigation Method: Students can navigate in this virtual world using a hybrid navigation method that consists of the natural walking method, gazed-directed method, and target-based method.  Natural walking method is meant for short distance movement in which students position is tracked by the tracker attached to the HMD.  Gazed-directed method is used for remote distance navigation.  To navigate to a remote location, students just gazed in the direction that they wish to go and provide the specific “start gesture”.  To stop walking, they will need to give a command to the system by providing the specific “stop gesture.  Target-based navigation method can be used for immediate transfer between take-off and landing sites.

Control panel: The most basic task for students in this system is to find out how to pilot a hot air balloon.  In order to pilot the hot air balloon, students can access a control panel in the hot air balloon.  The control panel is illustrated in Figure 4. 

Figure 4 : A hot air balloon control panel

The basic components of the control panel consist of the temperature control slider, the altimeter, the variometer, the timer and the fuel indicator.   Among these components, only the temperature control slider is operable by students to set the temperature of the hot air balloon.  The remaining four components are all simulated in real-time to reflect appropriate current values.  The altimeter displays the current height of the hot air balloon. The variometer shows the current ascending/descending speed. The timer shows the time taken since the take-off.  The fuel indicator shows how much propane gas fuel is left for flying the balloon. 

Several additional components are embedded in the control panel to guide students in constructing knowledge on the physics principles.  These components are indicators that display the current properties of the air namely temperature, pressure and density in the hot air balloon and its surroundings.  These values are also simulated in real-time for different altitudes.  Finally, four additional graph visualizer buttons are provided.  Pressing any of these buttons launches the respective graphs.  One of the most useful graphs is the load chart that provides guidance to students on the temperature to be set in order to make the balloon take off.  The remaining three graphs show how the properties of the surrounding air (temperature, pressure, and wind speed) change with altitude.  Figure 5 illustrates a student selecting the temperature graph button of a control panel using the ray-casting method.

Figure 5: Accessing the control panel using the simulated ray

Virtual menu:  iHABS contains a virtual menu that enable students to activate certain system commands such as exit system, reset view, and reset simulation.  Figure 6 shows a student accessing the virtual menu.

Figure 6: Accessing the virtual menu using the simulated ray

Virtual toolkit: Students can gain access to a virtual toolkit (Figure 7) that allows them to change various parameters such as the balloon size and balloon load.  They can also observe how the changes in parameters affect the maximum height and ascending rate.  Students are also allowed to modify the weather conditions, specifically the ground temperature and sea-level pressure to enable them to find out how the different weather conditions can affect hot air ballooning.  

Figure 7: Virtual toolkit

Virtual keypad:  Upon selecting the temperature slider or any button on the virtual toolkit (except the "All Settings" button), a virtual keypad will be activated to allow students to key in a value for the selected parameter.  Figure 8 shows a student keying in a value using the virtual keypad.

Figure 8: Keying in a value using the virtual keypad

Empirical Study

An empirical study was conducted on the iHABS system to examine it on four dimensions, namely VR learning outcome and learning experience, collaborative VR
learning, usability of VR interface, and user experience.  The VR learning outcome and learning experience aspect explores the overall educational efficacy of VR learning experiences.  The collaborative VR learning aspect explores the effectiveness of collaboration in a networked, VR environment and assesses its implications for education.  The usability of VR interface aspect examines the efficiency of the user-system interaction techniques including navigation, system control, object selection, and the use of gestures.  Finally, the user experience aspect looks at users’ engagement, sense of immersion, and issues related to comfort level of the users with while using VR devices.

Figure 9 and Figure 10 shows some snapshots taken during the study sessions.

Figure 9: Two students collaborating in the iHABS learning environment

Figure 10: Two students enjoying their exploration in the iHABS learning environment

Constructivist Physics Lerning in An Immersive Hot Air Balloon Simulation Program (iHABS) at the ACM SIGGRAPH 2003 Conference, San Diego, CA, USA, 27–31 July 2003.

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