paper visualizing anuradhapura
TRANSCRIPT
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Visualization of Ancient Anuradhapura: ADemonstration of Digital Possibilities
Prasad Samarajiva1
, ChandimaAmbanwala2, Anuradha Piyadasa3
Due to human activities and natural processes ofdecay, many of the past superstructures inAnuradhapura are no more. Only a fewremaining structures point to the glory of thepast. Visitors are intrigued by the remainingsuperstructures and ancient foundations. Readinghistorical texts as well as recent archaeologicalpublications would fill in some of the gaps to thevisitor. In addition, the limited replicas of thestructures found in museums also help to somedegree. But the visitor's visual understanding isstill limited.
In the past few years, computer aided three-dimensional (3D) visualization has beengenerated for some notable sites in the West,such as ancient Rome and ancient Greece. Theygive a vivid display of these sites, especiallywhen some of these reconstructions areaccompanied by virtual reality. The
reconstructions present an immediacy which nohistorical or archaeological text could provide.
1 Royal Asiatic Society of Sri Lanka, Email:[email protected] Archaeology.lk, Email: [email protected] Royal Asiatic Society of Sri Lanka, Email:
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As a first experiment, our team has attemptedto visualise aspects of ancient Anuradhapurathrough computer aided 3-D technology
combined with global positioning. We havedeveloped the remaining structures usinghistorical texts as well as recent specialisedpublications. We thus developed 3D models forparts of ancient Anuradhapura using satelliteimages, photographs, and the commonlyavailable 3D visualization software called GoogleSketchup. In addition to computational graphical
tools, the combined knowledge of history,archaeology, architecture, art, and engineeringwas used in this modeling to represent these paststructures in the most accurate way. Such directvisualization of ancient heritage sites can beleveraged to better study these places as well asto raise awareness in general on the pastAnuradhapura society, as well as to give support
for pilgrims and the tourism industry. Whentransferred to a mobile phone, they could directlyact as a guide to visitors on the site. The paperdescribes the process of computer visualisationand illustrates through a live demonstration ourmodel of Anuradhapura.
Keywords: 3D Visualization, Anuradhapura, Google
Sketchup, satellite images, photographs
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Introduction
A visitor walking through the innumerable ruins in
Anuradhapura, the ancient capitol of Sri Lanka, maybe intrigued to know how these structures appeared
in their glory days. Reading historical texts as well
as recent archaeological publications would fill in
some of the gaps to the visitor. In addition, the
limited replicas of the structures found in museums
also help to some degree. But the visitor's visual
understanding is still limited. As a first experiment,our team has attempted to visualize aspects of
ancient Anuradapura through computer aided 3D
technology combined with geographical positioning.
We have used the remaining structures combined
with historical texts as well as recent specialized
publications in this attempt. We thus developed 3D
models for parts of ancient Anuradhapura using
satellite images, photographs, and the commonly
available 3D visualization software called Google
Sketchup. Presented below is a synopsis of tools and
methodologies, together with examples from our
model of selected parts of ancient Anuradhapura.
3D Modeling Technology
Computer-Aided Drafting (CAD), is the use of
software and computer systems to create virtual
models of physical objects. Geometrical data of an
object is usually recorded in a numerical format
together with material data of the object. The
material data includes color and texture of the
material. In addition to the geometry and materialdata, environmental data such as light sources can
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also be introduced to the model. The software uses
these data and graphically renders the object on a
computer screen from one view point at a time.
Similar to a motion picture, continuous rendering ofan object from a trajectory of viewpoints completes
the virtual visualization of the object. However,
unlike a motion picture with a fixed trajectory of view
points, the rendering viewpoint of a CAD models can
be interactively changed by the end user, thus giving
a sense of virtual reality.
Most of the available software maintains elementary
objects like lines, squares, circles, polygons, cubes,
spheres, cones, and cylinders. State-of-the- practice
software has built in capabilities for the user to
create an object of choice using the elementary
objects. We used commonly available free software
called Google Sketchup (SU) in this attempt to
visualize parts of ancient Anuradhapura.
Geographically Referenced Modeling
Google Sketchup is a specially designed 3D modeling
software to work with another software system
called Google Earth (GE). GE in essence is a virtual
globe program that shows the earth bysuperimposition of images obtained from satellite
imagery, aerial photography, and geography over a
3D globe. However, the data for GE is mainly stored
in remote computer system since a current day
personal computer is not sufficient to maintain such
a vast collection of information.
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SU can interact with GE to create global positioned
models. SU can selectively copy the terrain, and
imagery of a given geographical area from GE. Such
methods simplify the modeling process since thelayout and dimensions of a structure are readily
available. In the case of SU, it is possible to
superimpose one or many developed models in GE
for visualization. Such capabilities provide a highly
conducive environment for collaborative
development and sharing of models. Development
of the Jethavana Monastery of ancient Anuradhapurausing SU, GE, photography, and knowledge of
archaeology is described in ensuing sections.
Model Development
For the sake of simplicity, we selected the Jethavana
Image House (pathimagara) located within the
Jethavana Monastery for this illustration (Figure 1).This is a typical Anuradhapura and Polonnaruwa era
stone foundation and brick masonry structure.
Typical to an image house, the vestibule of this
structure leads to a circumambulatory pathway
around an inner chamber. The main entrance to the
image house is a 27 feet tall opening with monolithic
stone jambs. Fragments of the stone door headerappear to be still sitting on the vestibule floor. A
few complete stone window and door frames remain
intact to this day. A partially destroyed, perhaps by
treasure hunters, lotus pedestal (padmasana) is still
present in the inner chamber. Based on the size of
the entry door and the size of the lotus pedestal, the
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height of the original Buddha statue is estimated to
be about 37 feet (Seneviratna, 1994).
The original roof could have been a vaulted brickmasonry or a traditional timber hip roof cladded with
clay tiles. Based on Bandaranayake (2009), a
decently preserved roof structure from late
Anuradhapura era cannot be found present day.
Readership may wonder why walls of the image
house was abnormally wide. One possibility is that
the walls were widened to support the masonry
dome. However, the primary author is of the
opinion that the ancient builders thickened these
unbraced tall walls to provide adequate resistance
against lateral wind forces than to support the dead
weight of a masonry dome. Therefore, in the
current form, we assumed that there was a
traditional timber hip roof cladded with clay roof tiles
over the Jethevana Image House.
Senevirathna (1994) speculates this structure to be
the Manimekhala Pasada built by king Sena I in the
9th Century CE. C ava sa reports that the image
house was destroyed by Chola invaders during the
reign of Udaya IV (946-954 CE) and the king partly
rebuilt it. King Mahinda IV has restored the structureonce again in the 10th century CE. Based on the
C ava sa, the colossal Buddha statue could have
been a gold painted limestone statue. In essence,
the present ruined structure is a result of recorded
activities of construction, destruction, and
reconstruction over the last two centuries of
Anuradhapura era and, unknown acts of destruction
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by humans and nature in the following centuries.
Now we proceed to build the 3D model of the
Jethavana Image House with sufficient knowledge of
the history of the structure.
Graphical Development
In the first step of graphical development, we used
the partial satellite view of the Jethevana Monastery
through GE (Figure 2). In addition, this view shows
the ruins of other buildings and parts of the
Jethevana Stupa at the western boundary of the
monastery. Direct access to a satellite image
simplifies the correct global positioning and
approximate dimensioning of the model. It is also
possible to use a digitally scanned plan of the
foundation layout over the satellite image for more
accurate dimensioning.
In the second step, we traced the foundation layout
and developed the building footprint (Figure 3). The
layout was adjusted by comparing the available
photographs for accuracy. It is important at this
point to paint the foundation segments with the color
and texture of the superstructure walls that are
going to be there.
In the next step, we developed the walls (Figure 4).
This was a conjectural reconstruction of walls was
based on our historical and engineering knowledge.
Addition of door and window frames ensued. A close
review of these frames indicates that there were no
hinges in these frames to install operable door or
window panes. As a result, we assumed that the
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image house was never built as a fully closed
structure.
Following the walls, doors, and windows, wedeveloped the roof based on our assumptions of the
roof type. However, the roof system was graphically
grouped for easy replacement with a different type
of roof when more accurate information will be
available in the future. Addition of the architectural
details like the half moonstones (sandakada pahana)
and the lotus pedestals ensued. We also added the
peripheral structures including the two smaller
structures and the parapet for visual completeness
of the model. At this point the model was ready to
be placed in GE.
In addition to the Jethavana Image House, a number
of other identifiable structures including the sthupa
were added to the model later on. Figure 7illustrates the overall view of the Jethavana
Monastery in its prime during the late Anuradhapura
era. Figure 8 illustrates sunrise at the Jethevana
Bodhighara Railing site with the sthupa in the
background. Figure 9 is a present day view of the
pond near the Jethavana Uposathaghara and Figure
10 is the pond as seen in the model.
Digital Possibilities
These digital models of the structures in
Anuradhapura have been developed with the
anticipation of further improvements. Most of these
models can be edited and improved upon discovery
of additional information. Currently these models
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are available in the Google 3D Warehouse
(http://sketchup.google.com/3dwarehouse - search
term Anuradhapura) for anybody to download and
edit. We envision development of the entire ancientAnuradhapura so that a viewer can visualize the city
and the structures in a chosen time period of our
illustrious history.
Conclusions
We developed 3D models for parts of ancient
Anuradhapura using satellite images, photographs,
and the commonly available 3D visualization
software called Google Sketchup. In addition to
computational graphical tools, the combined
knowledge of history, archaeology, architecture, art,
and engineering was used in this modeling to
represent these past structures in the most accurate
way. Such direct visualization of ancient heritagesites can be leveraged to better study these places
as well as to raise awareness in general on the past
Anuradapura society. In addition, these models can
be used to support the tourism industry. When
transferred to a mobile phone they could directly act
as a guide to visitors on the site.
The current development is an effort by a handful of
volunteers with the interest in archaeology. We
envision further developments in a global
collaborative environment of volunteers.
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References
C avamsa: being the more recent part of the
Mah vamsa, Part 1, Wilhelm Geiger, Ceylon Govt.
Information Dept., 1953
Ancient Anuradhapura the Monastic City, Anuradha
Seneviratna, Archaeological Survey Department,
Colombo, Sri Lanka, 1994
Sinhalese Monastic Architecture: the Vihras of
Anurdhapura, Seneka Bandaranayake, OrientalBlackswan Private Limited, Hyderabad, India,
2009
Figure 1. Composite of Photos of the Jethavana
Image House
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Figure 2. Geographically Referenced Satellite Image
of the Jethavana Image House Captured by SU
Figure 3. Development of the Footprint of the
Jethavana Image House based on the Satellite
Image
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Figure 4. Development of the Superstructure of theJethavana Image House
Figure 5. Completed Superstructure of the
Jethavana Image House
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Figure 6. Illustration of Architectural Details of the
Jethavana Image House
Figure 7. Overall View of the Jethavana Monastery
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Figure 8. Sunrise View of Jethavana Bodhigara
Railing Site
Figure 9. Present Day View of the Pond Near the
Uposathaghara
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Figure 10. A Model View of the Pond Near the
Uposathaghara