P  R  O  J  E  C  T       M  E  M  B  E  R  S G R E G   H E C H T    Undergraduate, Computer Science P H I L I P   KIM   Undergraduate, Art and Design S A M   R A U C H  Graduate, EECS X I A O L O N G   Z H A N G  Graduate, SI

C O N T E N T S : 
 

• A c r o p h o b i a &  T r e a t m e n t
• W h y  V i r t u a l  R e a l i t y ?
• T h e  A c r o - V R  P r o j e c t
• P a s t  W o r k
• O b j e c t i v e
• P l a n  o f  A c t i o n
• T h e  M o d e l :
• O v e r v i e w  o f  t h e  M o d e l i n g  P r o c e s s
• C o u r t y a r d
• L o b b y
• E l e v a t o r
• P o p - U p  C o n t r o l  P a n e l
• I n t e r a c t i v i t y  a n d  S c r i p t i n g
• P r o b l e m s
• L i m i t a t i o n s
• R e c o m m e n d a t i o n s
• T h e  V R M L  M o d e l
 

A C R O P H O B I A
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   "A person suffering from acrophobia experiences a pervasive fear of heights that may interfere with their ability to do even the most mundane tasks  (e.g., they may not be able to park on the upper levels of a parking structure or even walk up a flight of stairs).   A number of sensations and feelings can trigger this fear:  seeing the tops of trees from a high elevation, seeing a bird flying below them instead of above, realizing how close they are to an open space, going up in an elevator and anticipating the height, etc." (Taken from Acrophobia '96 report)
 

T R E A T M E N T
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   "An effective treatment for acrophobia is a technique called "graduated exposure", whereby the patient is confronted with a series of anxiety-provoking situations, each more challenging than the last.  So, in treating an acrophobe, a psychiatrist might take the patient to the second floor of a building and make them look out the window, thus exposing them to their fear.  Once their fear of the second floor is gone, the patient is moved up to the next floor. And so it might progress, with the patient slowly moving up from floor to floor, each time waiting for their fear to disappear.  At the University of Michigan Department of Psychiatry, such exposure treatments are performed in the east elevator area of the main hospital.  The hospital is nine stories tall, providing a sufficiently strong anxiety-provoking stimulus for most patients."  (Taken from Acrophobia '96 report)
 

The East Elevator   site is shown here on this map of the UM Medical Center area. Note that the view from the East Elevator includes four nearby buildings and a courtyard.  In the distance, areas of UM's central campus can be seen.

W H Y   V I R T U A L   R E A L I T Y ?
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    "The UM Hospital Department of Psychiatry (DoP) would like to investigate the feasibility of using virtual reality models to treat acrophobes.   Eventually, they plan to conduct a study which compares patients' physiological (e.g., heart rate) and psychological (e.g., assessment of fear) reactions to the real and virtual environments.

    The results of such a study would contribute to the knowledge of acrophobia in general.   In addition, if the virtual environment could be used in graduated exposure treatments, the following benefits might be realized:
 

• Time/Convenience. The virtual reality equipment could be stored on site at the Department of Psychiatry, eliminating need to travel to the East Elevator location. Normal elevator passengers would not be disturbed by acrophobes undergoing graduated exposure treatment.
• Confidentiality. Because patients could receive therapy while in the office, they would not have to sacrifice confidentiality as they do when using the public East Elevator.
• Control of the Environment. The doctor can easily control the virtual environment - He cannot control the actual environment which is subject to unexpected situations (e.g., imagine an elevator malfunction!). This would allow the doctor to more easily control the progression of the treatment, as well as to investigate which perceptual cues are most influential to the fear. Cues could be added to or subtracted from the environment methodologically while acrophobes' physiological responses are monitored.
• Less intimidating. Patients may be more willing to try the virtual environment because they know they are safely planted on the ground."

 
 (Taken from Acrophobia '96 report)
 

PAST WORK: ENG 477   FALL 1996
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    In the Fall term of 1996, a group of 9 students developed the first phase of the Acrophobia Virtual Reality Project in Engineering 477: Principles of Virtual Reality.  Their work resulted in a VR model of the University Hospital's east lobby, an elevator and the surrounding courtyard in VRML version 1.0.   In developing the final VRML environment, this group created detailed AutoCAD models and utilized software packages such as WorldUp and 3D Studio to combine and export to VRML.  In the process, they left behind 580 files of 17 different file-types (3DS, DWG, DXF, MLI,  BMP, GIF, EBS, IV, JPG, MAT, NFF, RGB, TGA, TH, UP, WAV, WRL),  with minimal documentation.

OBJECTIVES FOR ACROPHOBIA TEAM 1997
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    The Fall 1997 team set out to continue the work of the previous group with the following goals in mind:
 

• Upgrade the model to VRML 2.0 and prepare it for use in the CAVE.
• Consolidate the hundreds of files left behind by the previous team's work.
• Create a clear road map of files, formats and development strategies.  Since future work will be done on the Acrophobia project, this will allow for a greater understanding of the various files types.

• Incorporate scripting and interactivity into the model.  This includes opening and closing elevator doors, selecting floors by pushing buttons in the elevator, moving the elevator up and down in response to button pushes, adding sounds such as floor announcements, and introducing birds and other moving elements into the courtyard.  Scripting functionalities were not available in VRML 1.0.
• Introduce collision detection to prevent the patient from "plummeting" out of the elevator.

• Reduce polygon count for speed and efficiency without loss of realism.
• Increase realism of smaller details: lighting, textures, additional world elements.

    (Original project proposal - '97) The work was divided into five sections: the courtyard model, the lobby model, the elevator model, the control panel model, and scripting.   The work was tightly integrated as the models needed to be properly aligned with each other in the VRML environment, and the scripting depended upon the creation of particular objects in the model.

    Before any work could be done, however, the tedious task of sorting through all the files from the previous group's work needed to be accomplished.  Each file was examined and determined whether it was actually used in the final model.  Many of the suffixes were specific to an application that was no longer used.  Ultimately, of the 580 files, 20 were actually used for the courtyard model, 5 were used in the lobby, and 2 were used in the elevator (this left 553 unnecessary files), including texture maps.  These files were moved to a separate directory, and became the 'base' files on which this term's work was done.
 

T H E   V R  M O D E L
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OVERVIEW OF THE MODELING PROCESS
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The process followed was a little different for each portion of the model, but in general, this is the process that was followed in creating the VRML2.0 model.
• Update AutoCAD models
• Fix geometries
• Add new objects
• Name the various objects consistently and meaningfully
• Aesthetic manipulation
• Import AutoCAD models into 3DS
• Add textures, colors, and lighting
• Create simple animations
• Integrate some subsets of the AutoCAD models
• Scripting
• Export 3DS models to VRML2.0
• Add more complicated animations and scripting through direct editing of VRML2.0 files
• Integration
• Import VRML2.0 models into CosmoWorlds to correctly place the various sub parts and create the final VRML2.0 files
The sections below which address each portion of the model give more specific details about what was done in the creation of the various parts.
 

The Panoramic View
 
    In addition to the 3D buildings in the courtyard, the surrounding world needed to be rendered in a panoramic manner to convey a sense of realism.  The previous group simulated the far buildings and the horizon by wrapping a panoramic texture map image onto a parabolic surface.  This was lined up with a viewpoint from the elevator.  An image of this is shown below.
 
    While this initially appeared convincing, it was not ideal.  First, the panorama contained the same buildings that were being rendered as part of the courtyard.  This reduced believability for the astute viewer since images were redundant.  Also, the parabolic surface contained a considerable number of polygons.  At the start of this year's project, it was thought that the panorama could be created using VRML2's background node.  However, since the world was placed at the center of the background cube, positioning was difficult and the viewpoint from the elevator lobby looked odd.  Ultimately, a panoramic shape similar to the original design was created.  Taking two partial cylinders and applying a texture map of the horizon proved to retain visual effectiveness and reduce the number of polygons.
 
 

The snapshot below shows the horizon used on the backdrop.
 

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The Courtyard and Near Buildings

    The courtyard and adjacent buildings needed to be modeled at a closer distance in order to create motion parallax from the viewpoint.  As the viewer changes position at the window, his view changes, and motion parallax is evoked.  Simulating this motion parallax was important in order to give the viewer the perception of depth and height.

    The previous group created a planar grid and curve for the courtyard lawn and sidewalk.  For the nearby buildings, flat planes were created and each saved in separate 3DS files.  These files were named with the numbers 1 through 14.  No documentation was left as to which plane represented which building.  This term, in order to consolidate files and create a more usable world, those 14 planes and the lawn and sidewalk were combined into a single AutoCAD model.  Unfortunately, though not surprisingly, the scale of the lawn and that of the buildings was different; and much time was spent trying to find the correct ratio of sizes.  In order to create the buildings which would receive texture maps, surfaces were then applied to the planes.  The textures were applied in 3D Studio; but the translation and rotation of the textures was often incorrect, requiring adjustments by hand.

    Originally, the only additional elements in the courtyward were images of trees mapped onto rectangles.  This was a good attempt, given the capabilities of VRML 1.0, but looked unconvincing as the user moved up the floors of the building.  We felt that a three-dimensional solution would be more convincing.  Trees were created in 3D Studio by overlapping several twisted and warped spheres and placing them over another distorted cylinder for the trunk.  Bushes were created by scaling down the tops of the trees.  This created nice looking 3D objects in the courtyard that were viewable from any angle, and had depth that showed in the reflective nature of the sphere's contours.  The downside in using this method is that it requires a multitude of vertices to define the plants, which slows down the model on less powerful machines.  Several trees and rows of bushes were included.

    To increase the realism and the sense of height, birds were added that fly around the courtyard.  These are inlined worlds that create and translate polygons in the shape of a bird flying in a circle.  They were taken from the "Tenochtitlan" VRML world at http://vrml.sgi.com/handbook.  A few birds were placed near ground level.  Others were placed at higher elevations in order to be seen from the upper floors of the building.

    Another minor adjustment was made to the lawn of the courtyard.  The previous group used a texture map that was green, but contained many specular highlights that made it look like something other than grass.  Photoshop was used to darken and smear this texture to create a more aesthetically pleasing surface.  A texture map of dirt was applied to the sidewalk, but at present is not satisfactory in appearance.
 

Detail views of the new courtyard    

    The elevator lobby was created using the model constructed by the previous group.  This model was quite well done in that its architecture properly resembled that of the actual site. Therefore, rebuilding the entire lobby was determined to be unnecessary.  It was imported into AutoCAD R14 and minor adjustments were made so that all the geometries were in proper alignment.   Moreover, the model was edited to insure that all appropriate objects were solids and consistently named for use in 3DStudio.  Extraneous elements such as a highly detailed plant were eliminated from the AutoCAD model since it increased the polygon count and obstructed the view of the window where the acrophobic patient would look outside.  The lobby was then further modified in 3D Studio Max.   Textures from the old model were not authentic to the actual site. Therefore, photographs of the walls, ceilings, signs, and buttons were taken and manipulated using Photoshop.  These textures or their colors were used in 3D Studio to create a more true-to-life model of the lobby.   The final touch was that of lighting, also done in 3DS.   Lighting contributes greatly to the level of realism in the model since it gives tonal variations and shadows to the many surfaces.

    The elevator was remodeled using AutoCAD and 3D Studio Max.   While the actual scale and detail of the older elevator were convincing and accurate, problems with this model occurred when portions of the paneling and exterior frame did not render completely in updated versions of the various applications.  By using parts of the older model as a template, a new elevator was constructed in AutoCAD R14 and further modified in 3DS MAX.    This proved to be the most effective method of modeling for two reasons:  The elevator made by the previous group was constructed with great precision, and it needed to fit seamlessly with the other preexisting elements.  In addition, since the older textures of the elevator did not match the real elevator, new images of the real location were then taken, manipulated in Photoshop and added to the model. As with the lobby, the various geometries in AutoCAD were re-named in such a manner that they could be easily recognized when imported into 3DS.

    Two control panels were to be placed in the elevator.  The previous group had constructed a realistic copy of the actual control panels at the University hospital, and they are used in the present model.  The various geometries in this model were also meaningfully renamed for use in 3DS.  While we eliminated some elements, on the whole, the panels were used with their original geometries. Numbers for the various floors were added on the side of each button, as well as a viewing panel that identified the floor where the elevator stopped.    Textures were then added from pictures of the actual control panel to extend its level of realism.  (NOTE: Images of the control panel are included in the section on the new pop-up control panel.)

POP-UP CONTROL PANEL
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    In addition to the control panel situated permanently in the elevator, another set of controls were created in order to allow the user to access the functionality of the elevator outside the physical confines of the elevator.  This control panel is activated by pressing on a red sphere,  which pops up an exact replica of the elevator control panels.   These panels then follow the user throughout the environment. This allows a user to move outside the lobby and elevator, where they can get an overview of the whole model, and still control the elevator.     (NOTE: The images below include an image of the old control panel that was not a pop-up object!)

 

INTERACTIVITY AND SCRIPTING
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The original Acrophobia group created the model with the intention of adding interactivity to it. They created all the appropriate control objects, like the floor buttons in the elevator, but were limited by the capabilities of VRML 1.0. This time, we had the added benefit of access to VRML2.0 and were able to add much of the originally intended functionality.  The scripting added to the model falls into 3 major areas: Elevator Controls, Pop-up Control Panel and Miscellaneous.
 

• Elevator controls
• Floor buttons: The floor buttons were scripted to respond as much like an ordinary elevator as possible. The user can select a destination floor by pushing the appropriate button and the elevator will move to the appropriate floor.  Upon arriving at the given floor, the model is updated to reflect the current floor, by changing such things as the floor markers on the the wall and the control pane.  Scripting this interaction proved to be a minor challenge as the movement of the elevator is related to both its current position and the intended destination. The details of the floor movement script were initially worked out using simpler models with only a few relevant objects, and later incorporated into the larger VRML2.0 world.
• Open and close buttons: The doors of the elevator can be opened by pushing on the "up-down" button in the lobby and opened or closed by pushing on the appropriate buttons in the elevator.
• Sounds: All of the elevator interactions have associated sounds which increase the reality of the experience. A voice in the elevator informs the user whether the elevator is moving up or down and tells them what floor they have stopped at.  The doors also make appropriate sounds when opening or closing.
• Pop-up Control Panel

A pop-up control panel that follows the user around was added to the VRML2.0 model. It can be toggled on and off by clicking on the little ball that follows the user around in the lower right. This pop-up control panel has all the functionality of the control panel in the elevator. When the pop-up control panel is turned on, it can be moved closer to or further from the user by dragging the mouse over a little blue cylinder that appears near the sphere.
 
• Miscellaneous controls

A couple of interesting miscellaneous controls were added to the control panel:
• Lighting: The user can toggle the lights in the lobby on or off by clicking the yellow button on the control panel
• Invisibility: The user can make the walls of the elevator partially invisible by clicking the red button on the control panel. This allows him to see the ground moving away as the elevator goes up.

 

Files

    Dealing with all of the inhereted files turned out to be a rather difficult process.  There was a large number of files and little information about their contents.  We had to inspect each one to figure out exactly what it was and where it could be used.
 
The Previous Model

    The models from the previous group were meticulously crafted, however there were problems with the amount of detail as well as the surface normals.  Some details were seen as unnecessary, but they were difficult to eliminate due to the fact they were parts of solids in the AutoCAD models.  Some of the surface normals were reversed and the surfaces did not appear when imported into 3D Studio Max.

Hardware/Software

    The hardware and software proved at times to be unstable and buggy.  Computers were sometimes inaccessible, due to the limited resources in the VR Lab.  We also encountered numerous problems in trying to update files based on previous software versions and old standards.  One example is that a complete model of the elevator and lobby had to be redone; The transition between versions of WorldUp and AutoCAD reversed many of the normals, causing the surfaces to render incorrectly.  Other frustrations arose in making VRML2.0 files run consistently between the SGI and NT platforms, particularly with respect to the scripted interactivity.

Merging of VRML Models

    Upon the completion of the VRML models of the courtyard, elevator, and lobby, the worlds were merged to form the single ACRO world. At this time, it was realized that the courtyard was approximately 3 times the scale of the lobby and elevator. This was a difficult problem to predict: although the elevator and lobby were exactly measured and modeled, the buildings of the courtyard were modeled on a relative scale-done so they look approximately correct. The differing scale only became evident when the elevator moved up/down floors; since it was only 1/3 scale, it appeared the elevator wasn't moiving far enough.

The first attempted solution was to triple the distance travelled by the elevator. This made it so each floor had the correct view of the courtyard. But ultimately, felt unnatural in the time the elevator took to travel 3x its height and in the enormous height of the trees. The courtyard was then scaled using CosmoWorlds, making it of an equal scale to the lobby. Problems with the avatar arose following this, as it seemed that when the viewpoint was switched to one of the courtyard, the avatar was also scaled down. This was solved by routing the courtyard viewpoints into an avatar that was 3 times the size of the avatar in the lobby. This solved all scale problems.

Texturing
    Much of the lighting and texture mapping for the VRML worlds was done in 3D Studio.  For the courtyard, it was extremely important that the texture maps line up at the edges, so that a building's roof matches its walls.  However, it was difficult to control the manner in which 3DS created texture coordinates.  CosmoWorlds was used to correct this, but this introduced other errors as CosmoWorlds did not recognize or read some of the VRML nodes created in 3DS.
 
 

LIMITATIONS OF THE CURRENT MODEL
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What? No CAVE?
A surprising limitation came in the realization that the development for VRML2.0 and the CAVE were largely separate tasks.  The CAVE is still limited to VRML1.0 based Inventor files and offers no simple means of scripting.  It was decided to focus the development on the VRML2.0 model, which is web accessible, and should soon be readable by the CAVE system.

Performance
Our current VRML2.0 world includes many polygons, particularly in the courtyard portion of the model.  Due to this fact, it only runs well on high-end machines.

Scripts
We were never able to resolve the problem we were having with trying make our scripts run on both the SGI and NT machines.  The current scripts in the VRML2.0 model have only been verified to work correctly on SGI machines running CosmoPlayer 2.0.
 

RECOMMENDATIONS
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    The entire purpose of this project - immersive, phobia treatment - is contingent on transferring the model into the CAVE environment.  Thus, it should be an immediate priority to convert the model into a compatible format for CAVE simulation.  This should be simplified in the near future by a VRML2.0 compatible CAVE.
    It would also be of use to figure out how to reduce the complexity of the model and work out the details of writing the scripts to work on NT machines as well as SGI machines.  Reducing the complexity would allow the model to run on less powerful machines.
    We have put together a "roadmap" of the files used in the current model.  It should be of assistance to anyone who is interested in further developing the Acrophobia project.

THE VRML MODEL
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You've read about it, now see it for yourself!  Download the VRML version of our model.

** NOTE: Due to the size of the model and the VRMLscripting, this model works best on high-end machines. We have found it to work best on SGI workstations running the Cosmoplayer plugin.