Overview
Purdue University Calumet’s Visualization Lab resides in Powers 108, just off the main computing lab. The Vis Lab provides a means for faculty on campus to develop visualizations for both research and educational purposes.
The center piece of the lab is an immersive virtual reality system called a VisBox. In the VisBox, users wear glasses that allow them to see data and imagery in 3D. In addition to the visualization, the VisBox tracks the user’s movement and allows them to interact with the environment using a device called a wand. Vis Lab staff helps faculty become acquainted with the hardware and software used to control the VisBox, and assist in creating projects that can enhance research and/or be used to engage students by augmenting existing curricula.
In addition to the VisBox, the Vis Lab utilizes high-end graphics workstations and is engaged in research with remote visualization, augmented reality, haptics, and using consumer level devices for visualization such as the Nintendo Wii.
Hardware: VisBox
The VisBox is an immersive virtual reality system that allows a user to see and interact with data and objects in a 3-Dimensional space. The VisBox display consists of a 7’6” x 10’ rear projected wall, and a floor screen of the same size that users can stand on. Combined with 3D glasses, this configuration allows users to stand inside a visualization, with imagery coming out of both the screen in front of them and the floor beneath them.
The system uses four projectors (two per screen) to provide the 3D imagery (called Stereoscopic 3D, or S3D). Filters that are built into the projectors, correspond with the special lenses in the 3D glasses so that each eye only sees an image from one projector in a stereoscopic pair. The 3D images are sent to the project from a high end PC with four video outputs.
The system tracks a user’s head movement and hand location using a tracking system from Intersense (IS-900). The tracker has 6-DOF (Degrees of Freedom), referring to 3-DOF position (X, Y, Z) and 3-DOF rotation. So the system knows where user is located in the 3D space, which direction they are looking, and using a device called a “wand” the system also knows where a user’s hand is and the direction they are pointing. Using 6-DOF tracking, combined with a number of buttons on the wand, it is possible to program applications that allow users to interact with data and the environment, and manipulate objects intuitively.
Software: VR Juggler
Due to the nature of immersive VR systems at educational and research institutions, there is very little commercial software available that suits the visualization needs of our faculty. So, the majority of the software used in the VisBox is a mixture of OpenSource and in-house code. One of the more popular OpenSource projects for VR application development is VR Juggler. Originally developed at Iowa State’s VRAC, VR Juggler takes care of the more difficult and tedious aspects of VR programming such as displaying 3D images on multiple screens of arbitrary size and location, and utilizing various tracking systems and input devices. Using VR Juggler allows a programmer to focus at a higher level on the visualization itself and any interactions that might occur. VR Juggler can run in a simulator mode, which allows programmers to develop applications on regular PC displays, and run them on the VisBox without needing to recompile their code.
