Virtual Reality/CAVE Software?

WorthlessManatee asks: "I work for a company that is in the beginning stages of constructing our own CAVE and I would like some advice on a few topics. Which hardware vendors should I go through? I know of Fakespace, but are there other vendors I should be looking at? What software solution works best for a CAVE? So far I know of: VR Juggler, DIVERSE, and CAVELib? What are the pros and cons of each of them? Answers to these questions and any other hints or experiences you would care to share would be most appreciated. Thank you very much."

Comments

The UAEU-CAVE experience

[aokeil]

What do you mean by "constructing our own CAVE"? Really constructing your own CAVE as we did at the department of Architecture, UAEU? or have a company construct it for you?

In our case I selected to construct it myself using of-the-shelf components. We have a cluster of 3xP4s + windows 2000. more info found at: http://www.engg.uaeu.ac.ae/a.okeil/uaeu-cave/

A nswers to your questions depend on several determining factors such as:
1- What type of applications will you display?
2- Do you need navigation+interaction or only navigation? What type of interaction.
3- Do yoiu plan to integrate other input devices? tracking systems?
4- How do you plan to create your applications (on the long run might cost more than the initial cave investment).
5- Is the cave ment to be a showcase for your company or is it for internal use?.

In our case simplicity of creating the application came before anything else. We selected to start with programs students of architecture already use such as AUTOCAD, 3DS MAX and FormZ. The models are exported to the VRML format. The model is then displayed using a web browser + the cortona plug-in. A small application was developed to synchronize events on all screens. That is all you need to navigate through a virtual world in our cave. I think it can never get simpler. If you need some interaction then you have to start working on the VRML level using VRMLPAD for example.

This approach has saved us and our students the hasle of going into programming in languages none of us know. In 5 minutes you can have your 3D model out of Autocad running in the cave. I hope this reply answers some of your questions. Let me know if you have other questions.

CAVE issues...

[cr0sh]

Something that rarely thought about until it is encountered in the actual system, is projector registration.

There are basically two kinds of CAVE projector setups

1. A single, high-frequency (read that as big $$$$) projectors (120 Hz+), which use "flicker goggles" (though at these high frequencies this is rarely an issue) - like CrystalEyes glasses or something similar.

2. Dual projector systems (lower frequency projectors are cheaper) which use polarizing filters and similar glasses, each projector getting a different view from the rendering engine PC for the 3D effect.

The problem with the second system, while it can be cheaper (plus you don't have to deal with issues of wires or batteries in the glasses, just use cheaper polarized glasses - nearly throwaway), is the problem of registration - how do you get both projectors to overlay the image the same on the screen without undue distortion (keystoning) - if you place them side-by-side, you have an issue, same with on top of each other (plus there are ventilation issues, but that is another topic).

Ideally, you would want to use a prism or something to combine the sources - but this opens up other expenses (as well as light-loss issues, which will already be an issue with the polarizing filters).

Just keep it in mind as you build or consult on this system. The registration issue may not seem like much, but it can easily cause eye-strain and other issues when in use, and you will already be fighting physiological symptoms (ie, simulator sickness) just because it is a full or near-full immersion system...