CAVE Navigation System Using Game Controllers

Nick Gentile (ngentile)
Mieko Furuhashi (mfuruhas)

Introduction
System Requirnemnts
- Hardware Requirnments
- Software Requirnments
Usability Studies
Time Line
Project Result
- VR Juggler Installation
- VR Juggler Configuration
- Gamepad
- Applications
- Conclusion
References

Introduction

The navigation systems in 3D environment is not yet developed to sophiscated level, and the user experience of the navigation system is awkward. In this project, we will adopt various game controllers into the CAVE.
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System Requirnments

Hardware Requirnments

Display System: CAVE
Input Devices

Wand
Our $2,500 CAVE wand.
Gamepad(Logitech® Cordless RumblePad™)
JoyStick(AVB Feedback Pegasus Joystick)

Software Requirnments

vrNav2.0
vrNav is 3D scene navigation program for viewing 3D models in a virtual reality environment. The vrNav program provides following features:
- It allows you to load any model data formats that OpenGL Performer supports.
- The properties of the model are configurable.
- vrNav interchangeably supports many devices such as InterSense tracker, gamepad, joystick, keyboard/mouse, force feedback device, and racing wheel.
- vrNav is completely configurable by means of configuration files so that no programming changes have to occur and devices can be used interchangeably.
- vrNav supports multiple pipes, and stereo display mode operation.
- It allows you to make movies on the fly. Indeed, it also supports pre-defined path navigation.
OpenGL Performer
vrNav is based on the 3D scene graph toolkit OpenGL Performer.
VR Juggler
vrNav uses input device support from the VR Juggler.

Usability Study

Our hypothesis is that if a user has a video game playing experience then a user will have less difficulties using new navigational system which utilizes game controllers as oppose to those who do not have such experienes. We will prove this hypothesis by a survey and an experiment of two groups, one who has an experience in video game and the other group who does not have such an experience. A survey consists questions regarding a user's amount of experience in video games, and computer usage and in an experiment we will implement a treasure hunting maze and measure how long a user takes to acomplish the task.
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Time Line

Week	Date	Task
1	March 8	Study actualy game and find out the standards of button assignments.Create the standard for CAVE.
3	March 15	Spring break. (Catch up week)
4	March 22	Programming (create API)
5	March 29	Programming (create API)
6	April 5	Programming (create usability test) start recruiting usability study subject.
7	April 12	Usability Study.
8	April 19	Usability Study. Modify program according to the usability study. Write a report.

Project Results

VR Juggler Installation

We chose VR Juggler because of its support for a video game controller as an input device. More specifically, VR Juggler's "device manager", gadgeteer offered game controller support in it's CVS version for Linux. We looked at few other options but found that VR Juggler had the best documentation and support. First, we installed a pre-compiled version of VR Juggler. After that we got the CVS version, compiled it and droped the joystick drivers into the pre-compiled version. The reason we did this is because the pre-compiled version of VRJ seemed to be more stable and easier to work with.Initially we used VRJ 2.0 Alpha 3, but when they released Alpha 4 on April 30th we switched to that instead.

VR Juggler Configuration
VR Juggler is an ease to work with except when it comes to writing the configuration files. VR Juggler provides some configuration files which works well, however, when we attpemted to write our own for a John-e-box, we could not make it work at all.
In addition to writing configuration file for a john-e-box, we also had to write one for a game controller. Although, VR Juggler offeres a support for a joystick, they did not include a configuration file for it. We managed to write one for a game controller. The setup supporse to talk to a game controller through /dev/js0 port, however Linux did not recognize the device. It is not the problem between VR Juggler and Linux but it was the problem between Linux and hardware. We ran a test on Linux (jstest /dev/js0), the result shows that Linux did not find the device at this particular port.
Configuration File for gamepad
Applications

Maze
Files are available: Maze.tar.gz
An application we develop is a 3-D Maze. The user will navigate through the 3-D maze and search 3 treasures: water, fire, and earth. We would like to measure time taken, and users' ability to acquir objects in a virtual world. The problem we encounter is to make use of a wond joystick. When a joystick is at the center position, it return 0.5. However, when a joystick is moved, it returns a value greater than 0.5 regardless the direction of joystick.

Click image to enlarge

Docking
Files are available: Dock.tar.gz
This is reproduction of the experiment done by Shumin Zhai. The purpose of this application is to measure 3-D input device efficiancy and accuracy. It is a smiple application with two identical pyramids on the screen, one of them is fixed and the other is movable. The fixed one is a targed and indicated by dotted lines and its location is randomly chosen, and the movable one is a courser indicated by solid lines. Each line of a pyramid has unique color. Two pyramids are aligned when all the points and colors are aligned. A successful docking occurs when two pyramids are aligned for 0.7 seconds and within an allowed error. It measuring the actual distance a courser travled from the original location to the dock and time requried.

Click image to enlarge
Conclusion and Future Plans
Even though we did not accomplish the task we originally set out to do, we still found a lot of good to be taken away from the experience. For example, We learned how to install and configure (a little too late though) VR Juggler on several different platforms (mac linux cave). We also learned how to write and run VR Juggler applications on each of the platforms. VR Juggler is a great tool for creating virtual worlds. Unlike CAVE lib, memory managment is done by VR Juggler rather than a programmer. However, writing configuration files is a bit more complicated than anticipated. We also learned several things outside of VR Juggler. For instance, we learned some benchmarcks to measure efficiency of 3-D input devices. This helped us to determine what types of applications we wanted to implement in order to test our input device (joystick). For the future, we would first like to continue and finish what we have started. That is implement the joystick as a 6-DOF input device and test it in the applications we have written. Once we do that we would then like to port the joystick to an emersive environment like the CAVE. Eventually we would like to see the game controller become a standard input device.

References

Shumin Zhai, "User performance in Relation to 3D Input Device Design", Computer Graphics 32 (4), November 1998, p50-54, ACM
Frank Althoff, Herbert Stocker, Gregor McGlaun and Manfred K. Lang, "A Generic Approach for Interfacing VRML Browsers to Various Input Devices and Creating Customizable 3D Applications,"Web3D'02, February 24-28, 2003 Tempe, Arizona,USA,ACM
Robert M. Mulligan, Mark W. Altom, David K. Simkin, "User Interface Design in the Trenches: Some tips on Shooting from the Hip," 1999, ACM press
Carolina Cruz-Neira, "Surround Projection-Based Virtual Reality: The Design and Implementation of the CAVE,"1993, ACM.

Mieko Furuhashi
Nick Gentile

Created: March 8, 2004

CAVE Navigation System Using Game Controllers

Nick Gentile (ngentile)Mieko Furuhashi (mfuruhas)

Introduction

System Requirnments

Hardware Requirnments

Software Requirnments

Usability Study

Time Line

Project Results

VR Juggler Installation

VR Juggler Configuration

Applications

Maze

Docking

Conclusion and Future Plans

References

Nick Gentile (ngentile)
Mieko Furuhashi (mfuruhas)