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Reliving the Past
Archaeological sites brought to life through CAD and virtual reality Three-dimensional computer-aided design (CAD) models are playing an integral role in the virtual restoration of ancient archaeological sites, helping to preserve our cultural heritage by recreating ancient monuments in their original grandeur. Accurate 3D representations of real archaeological sites are being used for everything from education, to on-line meeting places for scholarly discussions and research, to entertaining and informing laypeople. One company dedicated to bringing the past to life is Learning Sites, Inc. (Williamstown, MA), a firm that specializes in the digital reconstruction of ancient worlds for interactive education and research. Learning Sites creates virtual worlds based on actual archaeological evidence reconstructed with an accuracy and sensitivity to known details that reflect the highest standards of scholarship. The archaeological data is integrated with advanced computer graphics techniques to further education, data analysis, and the preservation of cultural heritage information. Learning Sites’ vision is to create a globally integrated and interactive system of linked virtual worlds that can be used for teaching, research, archaeological fieldwork, museum exhibitions, and even tourism. "Our cultural heritage is slowly eroding," explains Learning Sites president, Donald H. Sanders. "Ancient archaeological sites have been vandalized and damaged, and most of them naturally erode over time. Visual representations of those sites, like slides or photographs, suffer from image degradation after many years. Thus, what we are witnessing is not only the deterioration of the actual antiquities themselves, but also of the only surviving original visual records of those monuments. Sites once accessible to scholars and the visiting public are rapidly disappearing and, as photographic emulsion peels off old glass plates at an alarming rate, documentation of these places is disappearing as well." It was these realizations that led to the idea of applying CAD (and associated graphics) programs to addressing this situation. "CAD is an ideal medium for accurately capturing and preserving the data," explains Sanders, "and it can reveal construction details that the archeologists never thought about before. Archeologists rarely deal in 3D, since they are usually sketching on paper. Because we are rendering sites directly in 3D and not flat two-dimensional representations of 3D, it forces them to study the evidence more closely than they are used to. CAD programs are much more accurate than pen and pencil drawings, down to many tenths of a centimeter. We will be modeling a corner and need to know very specific information about how the pieces of the walls are joined, which calls for much closer inspection than a field team is used to. This leads to much more realism in our renderings than the archeologists are used to seeing in drawings. A typical pattern we have encountered is that archeologists will be skeptical of the technology at first but when they see how much information it affords them, they want to do more with it. They quickly realize that the dynamic interaction between them and the 3D spaces allows them to understand ancient environments in ways never before possible." One current Learning Sites project is the digital reconstruction of the Northwest Palace of Ashur-nasir-pal II located in Nimrud, Assyria (present-day Iraq). The palace was built between 900 and 800 BC and was first excavated in the late 1840s. During this and subsequent excavations, many of the objects and artifacts were removed from the site and sold to museums, colleges and private collectors around Europe and the United States. As a result, hundreds of reliefs, statues and other artifacts were scattered across two continents, making it nearly impossible to imagine the palace in its original grandeur, or understand the material in its original cultural context. An archaeologist, Samuel M. Paley, Ph.D., State University of New York at Buffalo, and two architects Richard P. Sobolewski, R.A., Warsaw, Poland, and Alison B. Snyder, R.A., University of Oregon, have been researching the site for a book they are writing, having now located the original artifacts. Learning Sites is using the trio’s records to build a 3D CAD model as the basis for a virtual reality re-creation of the site for educational purposes. Thousands of photographs and drawings of the site are being scanned into computers; from the drawings, the models are being constructed in DataCAD by Richard Morse of DATACAD LLC (Avon, CT, USA). "We are rapidly developing a three-dimensional model from the basic sketches and surveys we have received from the archaeologists," explains Morse. "These drawings are scanned and imported into DataCAD where we can begin overlaying forms to create the model. DataCAD’s integrated modeler provides for the creation of complex forms and surfaces, yet is efficient enough for use in VRML models, which require conservative use of polygons. The resulting model is extremely precise and true to the field measurements used to create it. Frequently, this precision will present conflicts with the presumed construction of the site, and these inconsistencies have to be rethought and resolved by the archeologists. These changes can be easily made and allow us to develop variations that present different theories of reconstruction." Once these images are modeled and the collaborating archaeologists and architects have contributed the results of their analyses of the excavated evidence, it will be possible to see the entire palace as it once was, according to the best information that the scholars involved have been able to collect, with the original narrative and sculptural themes intact right down to details as fine as the texture on the walls. To further extend the value of this virtual world, Learning Sites intends to integrate the 3D CAD objects with a searchable, interactive database. Clicking on an object will bring up detailed information about it, such as its meaning or use and where the physical piece resides today. For example, clicking on a wall relief will result in a detailed close-up along with notes explaining that it is made out of alabastrous limestone, was used in religious or state ceremonies, and is currently residing in a particular museum. The information will also indicate the existence of any related pieces in other collections worldwide. The CAD models will thus become a device for cataloging and integrating the globally distributed artifacts with the original architecture. The artifacts may be viewed in the context of the reconstruction as well as in the display case in the museum. Slides of the site and its objects may will be scanned and made available for viewing within the VRML world. This allows instant access to views of the existing conditions, with the added benefit of being able to coordinate the images with the model to provide contextual reference. Scholars and students researching the site will feel as though they are visiting it, not merely reading about it. In addition, the clickable links are more flexible than a text-based search because people can click on items of interest rather than needing to know what terms to plug into a search engine. Interested parties can ask questions of the database (e.g. How many other sites have objects like this?) to get even more specific information. Programming the database in JAVA makes difficult-to-index facts more accessible than in a traditional text-based environment. Further, such 3D CAD-based virtual worlds allow viewers to experience the 3D space themselves while accessing information about the cultural and ritual significance of the palace and its rooms. The Northwest Palace is a mammoth project. The palace itself is over one thousand feet long and the Great Northern Courtyard, where the virtual reconstruction is beginning, is over ten thousand square feet. The sheer size of the effort, in combination with the wide distribution of many of the palace’s artifacts will probably double Learning Sites’ usual turnaround time for the creation of a 3D virtual world of a site this large. The work began this past summer and is not expected to be complete for at least three years. When the project is finished the virtual world will be available on CD-ROM, and parts will be accessible on the Internet. In the long term, Learning Sites plans to make this and its other worlds available to new audiences. An entire classroom will be transported to a remote archaeological site and be taught by a distant teacher. People all over the world will be able to tour the ancient wonders from the comfort of their homes. No travel costs, no jet lag and no lost luggage; just the Internet.

Reliving the Past

Archaeological sites brought to life through CAD and virtual reality

Three-dimensional computer-aided design (CAD) models are playing an integral role in the virtual restoration of ancient archaeological sites, helping to preserve our cultural heritage by recreating ancient monuments in their original grandeur. Accurate 3D representations of real archaeological sites are being used for everything from education, to on-line meeting places for scholarly discussions and research, to entertaining and informing laypeople.

One company dedicated to bringing the past to life is Learning Sites, Inc. (Williamstown, MA), a firm that specializes in the digital reconstruction of ancient worlds for interactive education and research. Learning Sites creates virtual worlds based on actual archaeological evidence reconstructed with an accuracy and sensitivity to known details that reflect the highest standards of scholarship. The archaeological data is integrated with advanced computer graphics techniques to further education, data analysis, and the preservation of cultural heritage information. Learning Sites’ vision is to create a globally integrated and interactive system of linked virtual worlds that can be used for teaching, research, archaeological fieldwork, museum exhibitions, and even tourism.

"Our cultural heritage is slowly eroding," explains Learning Sites president, Donald H. Sanders. "Ancient archaeological sites have been vandalized and damaged, and most of them naturally erode over time. Visual representations of those sites, like slides or photographs, suffer from image degradation after many years. Thus, what we are witnessing is not only the deterioration of the actual antiquities themselves, but also of the only surviving original visual records of those monuments. Sites once accessible to scholars and the visiting public are rapidly disappearing and, as photographic emulsion peels off old glass plates at an alarming rate, documentation of these places is disappearing as well."

It was these realizations that led to the idea of applying CAD (and associated graphics) programs to addressing this situation. "CAD is an ideal medium for accurately capturing and preserving the data," explains Sanders, "and it can reveal construction details that the archeologists never thought about before. Archeologists rarely deal in 3D, since they are usually sketching on paper. Because we are rendering sites directly in 3D and not flat two-dimensional representations of 3D, it forces them to study the evidence more closely than they are used to. CAD programs are much more accurate than pen and pencil drawings, down to many tenths of a centimeter. We will be modeling a corner and need to know very specific information about how the pieces of the walls are joined, which calls for much closer inspection than a field team is used to. This leads to much more realism in our renderings than the archeologists are used to seeing in drawings. A typical pattern we have encountered is that archeologists will be skeptical of the technology at first but when they see how much information it affords them, they want to do more with it. They quickly realize that the dynamic interaction between them and the 3D spaces allows them to understand ancient environments in ways never before possible."

One current Learning Sites project is the digital reconstruction of the Northwest Palace of Ashur-nasir-pal II located in Nimrud, Assyria (present-day Iraq). The palace was built between 900 and 800 BC and was first excavated in the late 1840s. During this and subsequent excavations, many of the objects and artifacts were removed from the site and sold to museums, colleges and private collectors around Europe and the United States. As a result, hundreds of reliefs, statues and other artifacts were scattered across two continents, making it nearly impossible to imagine the palace in its original grandeur, or understand the material in its original cultural context.

An archaeologist, Samuel M. Paley, Ph.D., State University of New York at Buffalo, and two architects Richard P. Sobolewski, R.A., Warsaw, Poland, and Alison B. Snyder, R.A., University of Oregon, have been researching the site for a book they are writing, having now located the original artifacts. Learning Sites is using the trio’s records to build a 3D CAD model as the basis for a virtual reality re-creation of the site for educational purposes. Thousands of photographs and drawings of the site are being scanned into computers; from the drawings, the models are being constructed in DataCAD by Richard Morse of DATACAD LLC (Avon, CT, USA).

"We are rapidly developing a three-dimensional model from the basic sketches and surveys we have received from the archaeologists," explains Morse. "These drawings are scanned and imported into DataCAD where we can begin overlaying forms to create the model. DataCAD’s integrated modeler provides for the creation of complex forms and surfaces, yet is efficient enough for use in VRML models, which require conservative use of polygons. The resulting model is extremely precise and true to the field measurements used to create it. Frequently, this precision will present conflicts with the presumed construction of the site, and these inconsistencies have to be rethought and resolved by the archeologists. These changes can be easily made and allow us to develop variations that present different theories of reconstruction."

Once these images are modeled and the collaborating archaeologists and architects have contributed the results of their analyses of the excavated evidence, it will be possible to see the entire palace as it once was, according to the best information that the scholars involved have been able to collect, with the original narrative and sculptural themes intact right down to details as fine as the texture on the walls. To further extend the value of this virtual world, Learning Sites intends to integrate the 3D CAD objects with a searchable, interactive database. Clicking on an object will bring up detailed information about it, such as its meaning or use and where the physical piece resides today. For example, clicking on a wall relief will result in a detailed close-up along with notes explaining that it is made out of alabastrous limestone, was used in religious or state ceremonies, and is currently residing in a particular museum. The information will also indicate the existence of any related pieces in other collections worldwide.

The CAD models will thus become a device for cataloging and integrating the globally distributed artifacts with the original architecture. The artifacts may be viewed in the context of the reconstruction as well as in the display case in the museum. Slides of the site and its objects may will be scanned and made available for viewing within the VRML world. This allows instant access to views of the existing conditions, with the added benefit of being able to coordinate the images with the model to provide contextual reference.

Scholars and students researching the site will feel as though they are visiting it, not merely reading about it. In addition, the clickable links are more flexible than a text-based search because people can click on items of interest rather than needing to know what terms to plug into a search engine. Interested parties can ask questions of the database (e.g. How many other sites have objects like this?) to get even more specific information. Programming the database in JAVA makes difficult-to-index facts more accessible than in a traditional text-based environment. Further, such 3D CAD-based virtual worlds allow viewers to experience the 3D space themselves while accessing information about the cultural and ritual significance of the palace and its rooms.

The Northwest Palace is a mammoth project. The palace itself is over one thousand feet long and the Great Northern Courtyard, where the virtual reconstruction is beginning, is over ten thousand square feet. The sheer size of the effort, in combination with the wide distribution of many of the palace’s artifacts will probably double Learning Sites’ usual turnaround time for the creation of a 3D virtual world of a site this large. The work began this past summer and is not expected to be complete for at least three years. When the project is finished the virtual world will be available on CD-ROM, and parts will be accessible on the Internet.

In the long term, Learning Sites plans to make this and its other worlds available to new audiences. An entire classroom will be transported to a remote archaeological site and be taught by a distant teacher. People all over the world will be able to tour the ancient wonders from the comfort of their homes. No travel costs, no jet lag and no lost luggage; just the Internet.

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