vr2go™ a new method for virtual reality development
TRANSCRIPT
VR2Go™ a new method for virtual reality developmentPhillip M. Sauter
PMS Microdesign, Inc.Pittsburgh PA.(412) 731-4004
1. Abstract
VR2Go™ is a new technology for developing virtual reality content that reduces software and hardwarecosts, utilizes generic Windows™ and Macintosh™ computers, eliminates the need for expensivegraphics workstations, expands the range of developers beyond the computer scientists and skilledprogrammers, enables all creative developers including children to create virtual reality content,expands the market by making the technology more accessible and revolutionizes virtual reality delivery(CAVE, Stereo Goggles, Virtual Desks, Web, CD/DVD, Multimedia, etc.).
2. Introduction
Virtual Reality concepts date back to around 370 B.C. with the writing of Book VII of the Republic byPlato. In the “Allegory of the Cave” Plato described a CAVE™ environment in which he explores theideas of perception, reality and illusion. Here is an excerpt from the book:
And now, I said, let me show in a figure how far our nature is enlightened or unenlightened: --Behold! human beings living in a underground den, which has a mouth open towards the lightand reaching all along the den; here they have been from their childhood, and have their legsand necks chained so that they cannot move, and can only see before them, being prevented bythe chains from turning round their heads. Above and behind them a fire is blazing at a distance,and between the fire and the prisoners there is a raised way; and you will see, if you look, a lowwall built along the way, like the screen which marionette players have in front of them, overwhich they show the puppets.
I see.
And do you see, I said, men passing along the wall carrying all sorts of vessels, and statues andfigures of animals made of wood and stone and various materials, which appear over the wall?Some of them are talking, others silent.
You have shown me a strange image, and they are strange prisoners.
Like ourselves, I replied; and they see only their own shadows, or the shadows of one another,which the fire throws on the opposite wall of the cave?
True, he said; how could they see anything but the shadows if they were never allowed to movetheir heads?
And of the objects which are being carried in like manner they would only see the shadows?
Yes, he said.
And if they were able to converse with one another, would they not suppose that they werenaming what was actually before them?
Very true.
And suppose further that the prison had an echo which came from the other side, would they notbe sure to fancy when one of the passers-by spoke that the voice which they heard came from thepassing shadow?
No question, he replied.
To them, I said, the truth would be literally nothing but the shadows of the images.
That is certain.
And now look again, and see what will naturally follow if the prisoners are released anddisabused of their error. At first, when any of them is liberated and compelled suddenly to standup and turn his neck round and walk and look towards the light, he will suffer sharp pains; theglare will distress him, and he will be unable to see the realities of which in his former state hehad seen the shadows; and then conceive some one saying to him, that what he saw before wasan illusion, but that now, when he is approaching nearer to being and his eye is turned towardsmore real existence, he has a clearer vision
In 1950, science fiction author Ray Bradbury wrote “The Veldt” where he describes a CAVE™environment. Here is an excerpt from that story:
They stood on the thatched floor of the nursery. It was forty feet across by forty feet long andthirty feet high; it had cost half again as much as the rest of the house. "But nothing's too goodfor our children," George had said. The nursery was silent. It was empty as a jungle glade at hothigh noon. The walls were blank and two dimensional. Now, as George and Lydia Hadley stoodin the center of the room, the walls began to purr and recede into crystalline distance, it seemed,and presently an African veldt appeared, in three dimensions, on all sides, in color, reproducedto the final pebble and bit of straw. The ceiling above them became a deep sky with a hot yellowsun. George Hadley felt the perspiration start on his brow. "Let's get out of this sun," he said."This is a little too real. (Copyright, 1950, by the Curtis Publishing Company)
In early 1963, Ivan Sutherland developed his legendary Sketchpad system. In 1965 he wrote “TheUltimate Display” that influenced a generation of scientists, computer artists, and media theorists. In1966, he invented the head-mounted display.
In 1992 the ”CAVE” (Cave Automatic Virtual Environment) was presented at the ElectronicVisualization Laboratory at the University of Illinois in Chicago, USA.
3. Virtual Reality
A computer-synthesized, three dimensional environment in which a plurality of human participants,appropriately interfaced, may engage and manipulate simulated physical elements in the environmentand, in some forms, may engage and interact, or with invented creatures. William R. Nugent, “VirtualReality: Advanced Imaging Special Effects Let You Roam in Cyberspace,” Journal of the AmericanSociety for Information Science, September 1991.
4. Cave Automatic Virtual Environment
A CAVE™ environment is a room where computer generated imagery is projected seamlessly on threeadjoining walls and the floor creating a realistic simulation of any environment. Think of it as aHolodeck®,
Fig. 4a CAVE™ orientation
5. Stereoscopic Viewing Goggles?
Stereoscopic viewing goggles® (Fig 5a) work on the same principal as the stereo Viewmaster® (Fig 5b)but provide full immersion and the ability to move about a virtual space.
Fig 5a. Stereo Viewing Goggles Fig 5b. Stereo Viewmaster®
6. VR2Go™ CAVE™ Computer Hardware Configurations
The hardware configuration for aVR2Go™ CAVE environment consists of Macintosh™ or Windows™computers organized into a cluster of three computers for a V-CAVE (Fig 6a) or five computers for atraditional CAVE (Fig 6b)
Fig 6a.V-CAVE configuration
Fig 6b. Traditional CAVE configuration
The following equipment was used in the development of the VR2Go™ technology.
Master Computer: 400mhz G3 Apple Powerbook or 600mhz G3 Apple iBook
Slave System 1: Left Computer: 1.3ghz P4 Win2000 with GeForce3 graphicsRight Computer: 867mhz G4 MacOS with GeForce3 graphics
Slave System 2: Left Computer: 1ghz G4 Apple Titanium Powerbook with ATI 9000Right Computer: 1ghz G4 Apple Titanium Powerbook with ATI 9000
Projectors: 2 ea. Viewsonic PJ500 short-throw LCD Projectors
Goggles: I-Visor stereo glasses
Head-tracker: Intersense Model 30
7. VR2Go™ CAVE™ Screen Configurations
The traditional CAVE configuration consists of four screens (three adjoining walls and the floor). Toreduce costs several V-CAVE’s were constructed using a wide variety of screen materials and sizes. Thefirst V-CAVE utilized two 19” monitors. This arrangement is used as the development platform,
Fig 7a. Monitor V-CAVE configuration Fig 7b. Cathedral of Learning V-CAVE
A six-foot front projection V-CAVE was developed for group presentations. It was constructed using1/2” plastic pipe and white window blinds. This cave configuration is portable.
Fig 7c. 1/2” Plastic Pipe Frame Fig 7d. White Window Blind Fig 7e. “The Secret Annex”
A four-foot rear projection V-CAVE was developed to provide a realistic CAVE experience. The frameis constructed with 1/2” plastic pipe with translucent white polypropylene screens. This caveconfiguration is portable.
Fig 7f. Front view of 4’ V-CAVE Fig 7g. Rear view of 4’ V-CAVE Fig 7h. 4’ V-CAVE screen
Several virtual environments have been tested with the four-foot V-CAVE. The Secret Annex asdemonstrated in the rear projection 4-foot V-CAVE.
Fig 7i. 4’ V-CAVE “The Secret Annex” Fig 7j. 4’ V-CAVE “The Secret Annex”
The Cathedral of Learning and The Virtual City as demonstrated in the rear projection 4-foot V-CAVE.
Fig 7k. 4’ V-CAVE “Cathedral of Learning” Fig 7l. 4’ V-CAVE “Virtual City”
Fig 7m. 4’ V-CAVE layout
8. Initial VR2Go™ Development
Virtual reality never lived up to its promise. Cost and the availability of developers have limited virtualreality development to large corporations, government and universities. Not having access to a full sizeCAVE environment prohibited such development. After learning that the University of Pittsburgh had aPC based CAVE™ environment we were granted access to their CAVE™ for the initial VR2Go™development. The University of Pittsburgh’s CAVE environment utilized four projection screens (threeadjoining walls and the floor) and operated on five Dell PC’s. (Fig 8a.) The initial test software wasdeveloped using pre-rendered images and photographs. A QuicktimeVR™ like environment providedsatisfactory results but did not provide any forward or backward motion. A real time 3D renderingengine was needed to generate CAVE™ environments. We integrated a cross-platform (Mac/Win)rendering engine that provided the most flexibility and performance. An initial test scene and softwarewere developed for calibration and analysis. After working with a calibration scene, a room withmeasured lines and colored blocks, we developed a real life scene of a grocery store. We continuedworking with the grocery store until we had proven our concept. (Fig 8b – 8h)
Fig 8a. CAVE with 3 adjoining walls & floor Fig 8b. Grocery Store scene view 1
Fig 8c. Grocery Store scene view 2 Fig 8d. Grocery Store scene view 3
Fig 8e. Grocery Store scene view 4 Fig 8f. Grocery Store scene view 5
Fig 8g. Grocery Store scene view 6 Fig 8h. Grocery Store scene view 7
9. VR2Go™ Technology
VR2Go™ is a new technology for developing virtual reality content that expands the market by reducingthe costs and complexity of virtual reality development. The VR2Go™ application requires a 3D sceneto be created in a 3D application such as Maya®, Lightwave®, 3D Studio Max®, KidsVR® or other 3Dapplication. A 3D artist creates a scene that contains all the 3D elements (models, cameras, lights,surfaces, key-frame animations, etc.) and interactive control information. The scene is exported in theVR2Go™ format.
The VR2Go™ formatted scene is copied to each of the computers. For a V-CAVE configuration, threecomputers are used, one master and two slaves. VR2Go™ applications are required for virtual realityscene playback, the master and slave. The master VR2Go™ application controls the cluster of slavecomputers through a high speed Ethernet network (10 megabit, 100 megabit, or 1 gigabit). In addition toCAVE communications, the master is responsible for all audio, input devices and user interface tasks.The slave VR2Go™ applications control each screen.
High-speed communications are an important component of any CAVE™ environment. A peer-to-peercommunications network using the TCP/IP protocol was developed. Once the Master has booted, itshares its IP address with all the slaves using simple file sharing. The slaves can now connect to thehost. After knowing the host’s IP address, the slaves then connect directly to the host in a peer-to-peerconfiguration. A server application is also available allowing many CAVES™ to communicate witheach other to create a shared environment. Other cluster communications formats are used includingUDP, serial and file sharing.
Peripherals connect to the master computer. Currently joysticks, head trackers, ultrasonic rangers, floorsensors and cameras are used. A serial and USB communications engine was developed to easily addperipherals.
Three-dimensional sound is achieved by two means; 3D sound software (creates a spatial illusion withtwo speakers) and 3D sound hardware (creates a spatial illusion with eight speakers placed in thecorners). All sound control occurs on the master.
Fig. 9a Stereoscopic Head Mounted Display
Stereoscopic vision is accomplished by using a separate computer for each eye that improvedperformance and image quality. This is an extension to the unified concept of having only one 3D scenecreated for all the viewing systems. A special adapter is used for LCD and DLP projectors for use in 3DCAVES™. Several manufactures produce VR glasses with separate inputs for each eye where anadapter is not needed. The same VR2Go™ scene is used for both eyes needing only an x-axis adjustmentfor high-resolution stereo.
10. VR2Go™ Real Time Rendering Engine
The rendering engine incorporates a multi-resolution mesh feature (a single high-resolution model!iscreated that allows the vertices to be removed. At run time the number of polygons can be dynamicallymodified depending on camera viewpoint, frame rate and CPU power), a subdivision surfaces feature (alow-resolution model is created and at run time triangles can be dynamically added for additional detail.Subdivision surfaces are well suited for terrains and curved surfaces), a physics engine (allows forapplying mass and elasticity to physical objects, applying impulses, forces or torques and settingmomentum and velocities), an advanced streaming, rendering and compression feature (the high-performance rendering engine produces maximum 3D performance and minimum sizes, hardwareacceleration (OpenGL and DirectX hardware accelerated rendering including lighting and transformscreates the fastest real time rendering. Software rendering for systems without hardware acceleratedgraphics), non-photographic shading effects (pencil sketches, comic book drawings and other drawingstyles can be used to render scenes and models), a particle system (Particles can be used to createrealistic effects to simulate dust, water, fire, smoke, explosions, vapors and sparks. Particles can rangefrom lines to points and from a couple to several thousand.!The color and direction can be set to simulatewind and gravity), key-frame animation (create 3D animations of grouped or individual objects in a 3Dworld. This industry standard method for controlling animations provides complex interactivity notpossible in linear animations), bones animation (real-time character animation utilizes bones to enhancequality, reduce development time and improves transmission time), level of detail (This feature providesa per-model control over the number of polygons used to render a model based on model’s distancefrom the camera), collision detection (this feature will allow a model to notify and respond to collisions),mesh deformation (this feature will allow the altering of the model geometry at run time to create bend,twist and ripple effects) and anti-aliasing (Anti-aliasing changes pixel shades along an object's border,blending line edges into the background image).
11. “KidsVR™” a Virtual Reality Tool for Education
KidsVR™ is built on VR2Go™ technology. This tool enables kids of all ages to create the future. Themove from two dimensions to three dimensions to virtual reality has not had a profound affect ontoday’s society. The technology has evaded all but a few highly skilled engineers and programmers. Thetime is now to expand the horizons of virtual reality by enabling artists and kids to lead us into ourtechnological future
KidsVR™ enables kids to create virtual reality. A simple tool set will unlock their creativity in ways wecan only guess. KidsVR™ will enable a child to create virtual reality using only basic shapes andmodels on a flat computer canvas. The child will choose a shape and place it on the canvas. This shapewill represent a location in 3D space. As these shapes are arranged on the canvas the child will becreating a 3D world. Anytime during the process the child can view their creation in 3D. Not only viewtheir creation, but navigate the creation on the screen, through stereo VR goggles or in CAVE™environments.
The KidsVR™ interface enable a child to quickly create a 3D scene. A simple on-screen menu systemaides ease of use. A File menu: Help (access help), New (clears canvas), Open (open saved file),VR2Go™ (learn more about VR2Go™ technology) and Make 3D (instantly generate 3D scene). A Sizemenu: Large (make selected object large), Medium (make selected object medium), and Small (makeselected object small). A Shapes menu: Sky (select sky texture), Plane (select ground plane), Cylinder(create of modify object as cylinder), Sphere (create or modify object as sphere) and Cube (create ormodify object as cube). A Texture menu is for selecting textures. Up to ten objects can be placed on the
canvas and arranged anywhere. (Fig 11b) The 3D scene can be viewed and navigated any time byclicking the “Make 3D” for instant gratification. (Fig 11c – 11d)
Fig 11a. KidsVR™ empty canvas Fig 11b Sky, ground and three objects
Fig 11c. Instant 3D scene (view 1) Fig 11d. Instant 3D scene (view 2)
12. VR2Go™ Applications (The Secret Annex)
VR2Go™ is a technology that reduces the cost of developing virtual reality experiences. This technologyrelies more on the artist, in this case a 3D animator and less on the software. A three dimensional scenecreated by a 3D animator can be visualized in virtual reality. This technology can be accessible usingMacintosh® and Windows® computers, not on expensive high-end graphic workstations.
VR2Go™ technology enhances existing multimedia technologies such as the web and CDROMs, butdelivers the most impact with stereo viewing goggles and CAVE™ environments. The stereo viewinggoggles work on the same principal as the stereo Viewmaster® but now support full immersion and theability to move about a virtual space. A CAVE™ environment is similar to the Holodeck® wherecomputer generated imagery is projected seamlessly on three adjoining walls and the floor.
The Anne Frank Experience will educate a new generation on the Holocaust. Virtual reality technologywill aide in bringing this new education experience into the 21st century. A generation brought up onvideo games, home computers and television will learn in an environment they are accustomed. Thedelivery mechanism is new the message is universal.
In the successful television show “Star Trek, The Next Generation” a “Holodeck” is used to simulatereal places. The technology used for the Anne Frank Experience will provide a historical accuratesimulation of the Secret Annex. Stepping into a CAVE™ environment or strapping on stereo viewing
goggles transports you back to 1942. Most aspects of life inside the annex can be simulated: day, night,ambient sounds and narration from the diary.
There are two exhibit display methods: CAVE™ environments and stereo viewing goggles. CAVE™environments can be oriented in several ways depending on space requirements. A V-CAVE is aCAVE™ like environment with two walls configured into a V with either front or rear projection. Anexample is the corner of a room. Two projectors project onto the two walls that make up the V-CAVE.For optimum viewing you stand in the entrance and look into the vertex. Six-inch thick Plasma displayswork where space is a premium. Conventional CAVE™ environments are viewed in a projection roomwhere the three adjoining walls make up the left, front and right screens and the floor. Standing or sittingin this environment places you in a virtual environment, in this case, The Secret Annex. Stereo viewingglasses produce the ultimate viewing experience and require less space and can be used almostanywhere. A secondary use for the CAVE™ environment is a virtual exhibit area or multimedia theater.
The goal is to create an accurate simulation of “The Secret Annex” as it looked and felt in 1942. Visitorswill be able to tour “The Secret Annex“ in New York, as part of traveling exhibits, on the Web or otherpermanent installations worldwide.
The Secret Annex project is currently ongoing. Two demo scenes have been developed to illustrate theconcepts of VR2Go™ technology and applying it to museum exhibit design. Both scenes weredeveloped using Lightwave®.
Fig 12a. 3D view of Secret Annex Fig 12b. 3D view of Secret Annex
Fig 12c. CAVE view of Secret Annex Fig 12d. CAVE view of Secret Annex
In the novel by Jack Finney “Time and Again” the protagonist Si Morley is transported back in time to1882 New York City by living in a 19th Century building for a period of time. The building was theDakota and was built in the early 1880’s. The room in which he lived faced Central Park, a view thathad not changed since that time. The transformation was complete. “Behind me and to the north I heard
a distant rhythmical jingle, perceptibly louder each time it sounded, and I turned to look back towardthe street once again. For a moment or two I stood listening to the jink-jink-jingle sound and then justbeyond the silhouetted branches, down the center of the lighted street, there it came, the only kind ofvehicle that could move on a night like this: a light airy, one-seated sleigh drawn by a single slim horsetrotting easily and silently through the snow.” (Copyright, 1970, by Jack Finney) Virtual environmentscan evoke a suspension of disbelief. History is best experienced.
13. Conclusions
VR2Go™ technology should expand the virtual reality market by increasing the number of developersand reducing the cost and complexity of such development. We welcome inquires and comments on thisnew technology.
14. Acknowledgements
Thanks to: Sharon R. Glick (Vice-President, PMS Microdesign, Inc.), Chaundel Sauter (MarketingResearch), Tom Dogg (Visionary), Scott Speedy (Lead Animation Designer), Eddie Rivera (Animator),Hans Westman (Art Institute of Pittsburgh), Sharon McGuire (Art Institute of Pittsburgh), David Barton(Art Institute of Pittsburgh), Kevin Abt (Student, Art Institute of Pittsburgh), Jeremy Jozwik (Student,Art Institute of Pittsburgh) and Jeffrey Jacobson (Dept of Information Sciences, University ofPittsburgh).
VR2Go™ is a registered trademark of PMS Microdesign, Inc.KidsVR™ is a registered trademark of PMS Microdesign, Inc.CAVE™ is a registered trademark of the University of Illinois
Copyright © 2003, PMS Microdesign, Inc.