ENG477 - Introduction to Virtual Reality
Fall 2006 - Final Project
PARSA (The City of Persians)
Amir Behzadan, Hiam Khoury
Faculty Advisor: Vineet Kamat
| 3DS and VRML Files (141 mb) |
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| Sample Video Clips (280 mb) |
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PARSA is an interactive Virtual Reality (VR) based tour of the ancient capital of the Persian Empire (Achaemenid Dynasty), the city of Persepolis.
The history of Persepolis goes back to 2,600 years ago when it was initially built by the first Persian king named Cyrus the Great. The site is marked
by a 125,000 square meter terrace partly artificial and partly cut off the mountain. It includes more than 10 palaces which served as residential
places, administrative buildings, and general audience halls.
Persepolis was destroyed approximately less than two centuries after it was built. Alexander of Macedonia plundered Persepolis and then set fire to
it in 330 BC. Today, Persepolis is not but debris. There are ruins of a number of colossal buildings, all constructed of dark-grey marble from the
adjacent mountain. A few of the remaining pillars are still intact, standing in the ruins. Several of the buildings were never finished.
In the presented project, we have modeled two of the most significant spots of Persepolis namely The Gate of Nations and The Apadana Palace.
The significance of these two locations are mostly because the former would be used by the official visitors and representatives of other local governments
to enter the capital city while the latter was basically the main audience hall in which the king would seat on his throne to meet people from all around the
country and delegates from neighboring governments.
By Definition, VR is the creation of real (as well as imaginary) scenes using computer generated graphics. Reconstruction of historical sites is one of the
main domains in which VR has been applied extensively for two main reasons. First, what remained from many of these sites is nothing but debris and
ruins and the only way to provide the visitors with views of how the site would look like is to recreate scenes from different perspectives and locations
of the real site using computer. Secondly, by providing VR tours of a remote site, one can access and view the historical place using his own computer
while staying home and without even spending a penny.
PARSA is significantly different from other existing commercial products about Persepolis in which it provides a high level of interaction with the virtual
world. The user can take advantage of looking at the 3D model from different perspectives while watching informative movies about the site and listening
to music. Traditional VR tours are mostly passive animations that take user along a set of predefined viewpoints without letting him pause or change
the animation flow and interact with it manually.
As described earlier, PARSA takes advantage of a built-in fully functional multimedia panel that allows the viewer to play, pause, and stop background
music and at the same time he is given the option to watch three different movie clips on a movie screen just to the left of the panel.
It also has a navigational compass which constantly shows the orientation of the viewpoint in geographical direction terms (e.g. North, Southeast, etc). While
the user is free to move around the site and enter different areas as an avatar, he can also use a set of predefined viewpoints which facilitates the navigation
and takes him to a number of favorite spots on the site.
Another useful feature of the application is an aerial map provided on the right corner of the panel. Not only does it it show most of the buildings in Persepolis from a top
view but it also has a number of touch sensors attached to each building on the map. Clicking on each of these touch sensors will display the name of the corresponding
building.
This map also serves as a navigation guide to the user for it has couple of viewpoints assigned to two of the touch sensors. The two touch sensors corresponding to
The Gate of Nations and The Apadana Palace are flashing on the map and by clicking on either of them the viewpoint of the user will directly change in a way that he or
she can observe each of these places clearly in his view.
We recommend using Internet Explorer and Cortona VRML to open the model. Although FireFox and CosmoPlayer can also be used, some features of the
model are best accessible in Cortona. Also, due to the large size of the main 3D model and multimedia files, higher frame rates and smoother scene rendering
will be achieved if all unnecessary applications are first shut down before opening our model. Having sound speakers is also recommended to listen to the music
and watch the movies.
We are using .avi video format in our model. During this project, we have experienced some problems in opening the video files on 3D Lab mainly because the
video file format we are using in our model was not supported by most of the lab computers. However, it turned out that our model works on almost every other
personal computer as long as it has a working copy of Windows Media Player and all the default video drivers installed.
Simply open the file in Cortona (recommended) or CosmoPlayer and start navigating in the site using either the predefined viewpoints or the avatar option. Make
sure that the gravity option is turned off so you can look at the site from above without the gravity forcing you landing on the ground.
You can also play a music file and watch three different movie clips. Also feel free to use play, pause, or stop buttons and enjoy the ultimate control over the multimedia
features of our model. One thing to remember is that since our video clips are all played on a single movie screen, you should either pause or stop a playing clip before
you can play another one.
As soon as the position and orientation of the viewpoint change, the built-in compass shows the updated viewing direction.
To walk directly into The Gate of Nations or The Apadana Palace, use the flashing touch sensors on the aerial map on the right hand side of the panel.
By pushing other touch sensors (shown in red color), you will be shown the names of each of the buildings inside the Persepolis.
The 3D file of the model has been created using 3D Studio MAX8. The model consists of a large number of standard as well as extended primitives. To create
a better impression, appropriate texture and lighting has been added to the elements of the model. A set of almost 20 cameras have been also integrated within
the scene.
The main source for a number of the textures we have used in our model has been the existing 3D models of Persepolis. However, in most cases, we have created
our own textures from scratch to add a little bit of innovation to our model. Since we wanted the model to run on both CosmoPlayer and Cortona, we had to
follow the limitations of the two VRML applications. Hence, we limited the total number of our light sources to 8.
Since we wanted the interior space of The Gate of Nations and The Apadana Palace to be visible to the user even when he or she is observing the scene from
distance, we decided to use transparent roofs for these two buildings. Other buildings which we did not model in our project are shown as simple boxes. We chose
to do so as opposed to simply not showing the rest of the site in our model because we wanted to include the overall layout of all the buildings of Persepolis. During
our class presentation, a very interesting question was asked by one of the teaching staff regarding the relatively small height of the entrance stairs compared to the
dimensions of other elements in the model. According to the historical texts, two main reasons can be noted to answer this question:
(1) The builders of Persepolis wanted the visitors to feel the large size of the buildings as soon as they start walking on the entrance stairs. So, they decided to
use shorter rise for the stairs in order to increase the total number of stairs on each ramp.
(2) Since horse riding was a common way of commuting in those days, they had designed the stairs in a way that a horseman can easily climb on them while he
is riding on a horse.
So, in designing the stairs, both architectural and human factors had been taken into consideration.
The most important issue was achieving an overall understanding of the model. This was done through several historical observations and archeological documents
available to us from books, pictures, videos, and a number of online resources. Since the entire site has been destroyed long time ago as a result of a bloody battle
between the armies of the Persian and Greek empires, for most parts of the site there are few or no visual evidence that help a computer modeler visualize and
reconstruct them in a virtual world. As a result, we tried to use a set of commonly accepted prescriptions and guidelines to create our model. That has led to some
differences in how our model looks like compared to other 3D models of the site that might be available to the user. However, we tried our best not to violate
any historical fact and keep the entirety of the real site in our 3D model.
Another issue was, as mentioned earlier, opening video files on 3D Lab computers. It turned out that this was not a direct problem of our model. After spending
several hours on the scripting of the model and running it on different computers, we figured out that the main source of the problem was the fact that the computers
in 3D Lab basically do not support our video file format. However, this should not be a problem for anyone who runs our model on his or her own computer as the
Windows Media Player by default has the appropriate driver required to play the video files of our model.
The main issue we faced during this project was the fact that many locations inside Persepolis just like several other ancient places around the world have been totally
destroyed as a direct result of wars, fire, and aging. So, there are a number of slightly different historical interpretations of how the real site would look like 2,600
years ago. We tried our best that our model complies with as many as these different archeological documentations.
Another important issue in our project has been the time constraints and the fact that modeling the entire site would take much longer than the project time we had
in one semester. So, we decided to choose two major locations inside Persepolis and model them in details while representing other locations using simple boxes just
to show the overall layout and dimensions of the site. We picked The Gate of Nations since it used to be the main entrance of Persepolis and also The Apadana
Palace as it was the main audience hall and the biggest building in the site.
We also had to spend quite a lot of time working on VRML coding part of the project since we wanted to create a fully functional multimedia panel for the user and
provide him with integrated music and video playing capabilities. We created a lot of scripts and used several routing commands and also spent a considerable amount
of time looking for useful and informative video clips and texture images of Persepolis on the web to include in our model.
This project has a potential for further improvements as there are still several other locations in the site that need to be modeled and integrated in our application.
It is a promising idea for possible future work by students of this class or anyone else who is interested in extending this work.
We took advantage of a number of available websites and documentations in order to verify our model and make sure it best represents the real site. These resources
were especially useful in choosing appropriate textures and dimensions for different locations inside Persepolis. Our cultural background helped us as well since we were
quite familiar with the location and history of the site.
Below is a list of some resources we used in our project:
Persepolis Recreated, a documentary book and DVD produced by Sunrise Film Co. (available at: http://www.sunrisefilmco.com)
This work has been done as the final project for ENG477 (Introduction to Virtual Reality) in fall 2006. We would like to thank Professor Beier and all his teaching assistants
as well as 3D Lab staff who have provided us with a significant amount of both theoretical and practical knowledge in the field of Virtual Reality.
We would also like to acknowledge related modeling work previously done on Persepolis. The outcome of our work does not mean to underestimate, criticize, or ignore the
results of valuable work done by experts in this field by any means since the objective of this project was to apply our learning of VR in a useful way.