Effective VR Visualization using Selectable Operation List
Shintaro Kawahara and Fumiaki Araki

The Earth Simulator Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan1Introduction

Visualization is a powerful measure to analyse threedimensional simulation data (also observation data) and to
extract information of specific physical phenomena that areincluded in it. In particular, the immersive visualization
environment (IVE) based on the technology of virtual reality(VR) is known as one of the effective measures to analyse suchthe complex data [1].
VR visualization on IVE has the following two advantages
as compared with desktop visualization. One is that user canunderstand easily and intuitively the three-dimensional structureof the specific phenomena in the simulation data. The other isthat IVE is better suited for pointing the exact three-dimensional
position, essential for the three-dimensional data analysis, than
the traditional operation using mouse and keyboard as the input
devices. On the other hand, there is a problem in thereproducibility of the visualization parameters that were set
interactively. Solving this problem will make VR visualization
more effective.
In this paper, we describe a method that used the history
information of user’s visualization operation for the purpose of
performing VR visualization more efficiently.
2

Problem of Interactive VR Visuali zation

In handling of various parameters required for visualization,
there is a fundamental difference between desktop and VRvisualization. In desktop visualization, the parameters areusually set by inputting values on command line directly ormouse actions on a graphical user interface (GUI). These
parameters can be confirmed as numerical values and easily
reused. In VR visualization, such parameters are set by user’sinteractive operations. It is difficult to confirm and reuse theseparameters because many of these programs do not havefunctions to do them.
We show a typical example of complicated structure of alarge amount of streamlines in Fig.1. Actually, it is impossible
to reproduce a same result of streamlines, because it is difficult
to locate the seed of streamline on the exact same place using
some pointing devices in the IVE.
In order to ensure reproducibility of characteristic threedimensional structures that were shown in Fig.1, it is necessary
to keep information of user’s visualization operations. One ofthe ideas to solve this problem is to implement undo and redo
function to VR visualization programs.
However, In these functions, users can only move backward(undo) and forward (redo) within the list of the recorded
operations, which includes large amount of unnecessary
operations. The efficiency of the data analysis in the VR
visualization can be improved, if we can extract only necessary
operations selectively.
3via Wi-Fi. Through Wi-Fi to send and receive information
between the IVE and the mobile device, users do not have tomove inside and outside of the IVE.

Selectable Operation List

The aim of this work is to improve the efficiency of VR
visualization by extracting only necessary visualization
operation selectively.
Fig.2 shows the system configuration of the prototype.
Mobile device is utilized to select necessary operation in IVE

Fig. 1 Interweaving Streamlines using VFIVE [2], VR
visualization program.
Mobile Device

IVE
Wi-Fi

VR
Visualization
ProgramOperation
List
Selected
Operation
List

GUI-based
Program toSelect
Necessary
Operations fromOperation List

Fig.2 System Configuration
In order to achieve this method, we performed followingthings;
A) implementations of the following two function to the VRvisualization program:
A1) the function to record user’s operations history,
A2) the function to restore only selected operations,B) consideration of the management methods of recorded
user's operation,C) and development of the user interface to select necessaryoperations.
In this experiment, we utilize BRAVE [3], which is a
CAVE-type VR system of JAMSTEC, as the IVE.

3.1

Record of User’s Operations
In this prototype, to implement the recording function ofuser’s visualization operations, we choose VFIVE. This isbecause that VFIVE is an open-sourced program and easy toexpand. The list of recorded operations is generated as a file ofASCII format data. Fig.3 shows an example of the operation listthat is generated by expanded VFIVE. User’s operations arerecorded as time series data.
Isosurface Scalar 1 t00
StreamLine Vector 1 x0, y0, z0
StreamLine Vector 1 x1, y1, z1
ColorContour Scalar 2 XY z0
Isosurface Scalar 2 t10
ColorContour Scalar 2 XY z1
Isosurface Scalar 1 t01
StreamLine Vector 1 x2, y2, z2
Fig. 3 An Example of Operation List
However, when the amount of these operations becomehuge, it is difficult to find only specified operations stored on
the operation list. For this reason, it is necessary to devise insome way that only important operations are presented to theuser. As a trial to solve this problem, we implemented thebookmarking function to VFIVE. Fig.4 shows the conceptual
diagram of this function. When characteristic structures werediscovered during visualization, user can record its timing as
bookmarks by using this function. By displaying only theprevious operations of bookmarks, the amount of informationthat is presented to the user is restricted.
We also implemented the function to restore visualization
operations that are selected by the client program.

Fig. 5 An Example of GUI Framework (Tree View)
References
[1]

[2]

[3]
Operation Started

Operations visualized
characteristic structures

Operation Finished

Timings that discovered
characteristic structures(= bookmarks)

Fig.4 Conceptual Diagram of Bookmarking Function
3.2

Development of User Interface
The operations shown in Fig.3 can be expressed as a tree
diagram, which is temporally called as “the selectable operationlist”, shown in Fig.5 when classifying each visualization method.
Such the diagram representation is effective to pick thenecessary operations from all of the operations. We developed aGUI program to generate the diagram automatically and to calleach operation selectively. In this prototype, we used laptop PC
in order to execute the developed program, though smaller
mobile devices such as PDA, smartphone, and tablet PC areuseful because these are lightweight when using that device inIVE.
4Conclusion

In this paper, we described a method using the selectable
operation list for the purpose of performing VR visualization
more efficiently.
As future works, we are planning to verify the effectivenessof this method and to apply it to the other mobile devices.

Andries van Dam, Andrew Forsberg, David Laidlaw, Joseph
LaViola, and Rosemary Simpson, “Immersive VR for Scientific
Visualization: A progress report”, IEEE Computer Graphics andApplication, Nov./Dec. 2000, pp. 26-52, 2000
Akira Kageyama, Yuichi Tamura and Tetsuya Sato,“Visualization of Vector Field by Virtual Reality”, Progress ofTheoretical Physics Supplement, No.138, pp.665-673, 2000
Fumiaki Araki, Hitoshi Uehara, Nobuaki Ohno, Shintaro
Kawahara, Mikito Furuichi and Akira Kageyama, “Visualizationsof Large-scale Data Generated by the Earth Simulator”, Journal of
the Earth Simulator, vol.6, pp.25-34, 2006