WARP: Team Delta



To make an interactive dome, there are a number of ingredients. Here's what we're using, what we've tried and what we'd like to try:

The Dome and Projector

We have a 5 meter inflatable dome. Inside, in the center, there is a modified Epson PowerLite 715c projector fitted with an Elumens lens for spherical projection.

The 3D Engine

The one requirement for a 3D engine in the dome is that it be able to output an image that is properly distorted such that when viewed on the curved surface of the dome it appears correct. This is called spherical projection. In the following two pictures, you can see the contrast between the 5 2D views and a combined, properly distorted image ready for projection on the 3D dome surface (click to view larger versions).

Coming into the project, there were no off-the-shelf, real-time spherical projection renderers readily available. Elumens, the makers of our lens, had released an API for spherical projection, but to our knowledge, no one had gotten it working with a commercial 3D engine.

Panda3D (Panda)- In talking with David Rose of the Disney VR Studio and the ETC Panda Team, we discovered that Panda has spherical projection code already. A special build was created for us, and we ended up using Panda3D for the semester.

Unreal Tournament 2003 (UT2K3, CaveUT) - Towards the end of the semester, Jeff Jacobson from UPitt got his CaveUT code working for domed output. Though the coverage is currently not as good as Panda's, UT presents a second 3D engine suitable for development.

Using Panda3D means that we can quickly adapt experiences made in the Building Virtual Worlds class. Here are a couple screenshots from two worlds that we adapted: Vengeance and Soapbox Racer.


We experimented with existing technologies such as DigitalSky by SkySkan. Using DigitalSky, we were able to verify that our lens and projector work. In addition, DigitalSky offers another (non-3D) paradigm for interactivity in the dome environment.

DigitalSky includes starfields, panoramas, scriptable shows, and pre-rendered movies. Here are images of a starfield with Mars superimposed, and an immersive movie of the Vatican.


We learned stitcher software as well, so that we could produce pre-rendered, non-interactive content as well. The image to the right (click to enlarge) is a test render from Maya that highlights the complexity of composing for a dome environment. Setting up the appropriate camera positions for all five views is the first problem to solve. Even with the correct camera position, the radiosity failed to render correctly.

Input Devices

Mouse: We found that the mouse was difficult to map correctly onto 3D space in the dome, partly due to guests preconceptions of how a mouse should work. Also, requiring a flat surface, the mouse is not a great input in general.

GyroMouse: We also tried a gyromouse which works like a mouse, but is not tied to a surface. The freedom of the gyromouse suggested a pointing style of interaction that it could not provide. Also, children couldn't get their hands around it to use it properly.

Trackers: We got magnetic trackers working inside the dome, although the location of the spacepad (antenna) was a tricky question. We decided the technology was too delicate and uncommon to use for our purposes. However, the 1-to-1 interaction of the trackers is still a desirable input.

ARToolKit: We tested computer-vision-based glyph recognition software (ARToolKit) in low-light conditions within the dome. Though we were able to get the system to work with relatively little light, the viability of glyph recognition is hindered by constantly changing light as the images projected on the dome shift.

Joysticks: With the proper mapping, we found that X-Arcade joysticks work well. They are also extremely easy to integrate with Panda, as they are essentially keyboard emulators.

Trackball: We got the X-Arcade trackball working, but didn't do enough exploration to really come to any conclusions.

Laser Pointers: In an effort to get another 1-to-1 style input, we attempted to get laserpointers working as input devices. Though we didn't succeed in implementing a laser pointer detection system, we have analyzed the dome for web-cam coverage. With 4 Logitech QuickCam 4000's we could get a large portion of the dome covered for laser pointer input.

Lilliput Touchscreen: We found that a touchscreen provides a successful interface, as long as the split focus between the dome surface and the screen is managed properly. With sound and visual cues, we were able to turn the touchscreen into a pretty solid interface.


Seating became a major issue as we noticed many children craning their necks frequently. Some even noted pain after the experience was over. Seating in the dome has a few requirements.

  • It should be low to the ground.
  • It should take up little space.
  • It should offer back and neck support.
  • It should allow the guest to lean back to view the dome.

Club Bean Bag Chair: These chairs were ok, but didn't offer enough back/neck support.

Folding Camp Chair: These chairs were too high, and took up too much space.

Video Rockers: Though these chairs are sometimes a little tough for adults to use, they are generally well suited to the dome. They are low to the ground, take up little space, provide the requisite support, and by their rocking nature, allow self-adjustment.

Other Technologies

Chromadepth: We're experimenting with Chromadepth glasses to see if we can get a viable 3D experience working in the dome environment.

A Chromadepth Model

Bass Shakers: We installed Aura Bass Shakers (AST-2B-4) in the video rockers to add a rumble at various points in the experience. This proved to be very effective, though it came at the cost of two of our audio channels.

© Spring 2004 The Interactive Dome Project
Carnegie Mellon University Entertainment Technology Center