Considered the largest virtual reconstruction, cultural heritage, and digital archaeology project to date, Rome Reborn is an international collaboration designed to create an interactive 3D digital model illustrating the urban development of ancient Rome. Rome Reborn 2.0 (alpha) made its debut on August 11 at Siggraph 2008 in Los Angeles.

In the scope of this project, the CityEngine has been applied to create thousands of Roman buildings and dozens of Ionic and Corinthian temples.

The detailed 3D models of Rome's monuments - such as the famous Colosseum and Ben Hur's Circus Maximus - have been created manually in several man-years of work by experts in archaeology and computer graphics over the whole world. To reconstruct the surrounding urban environment in similar detail, the CityEngine has been applied. Thus, over 7000 Roman buildings and in addition several highly detailed temples models have been generated with the CityEngine.

Area around the Circus Maximus rendered in mental images' mentalray^® (Circus Maximus model courtesy of Bernard Frischer, IATH)

Area around the Coloseum rendered in mental images' realityserver^® (image courtesy of Bernard Frischer, IATH)

“The CityEngine is a perfect match for the Rome Reborn project,” says Bernard Frischer, director of Rome Reborn. “Our project involves the complete virtual reconstruction of the city at its zenith under Emperor Constantine, when it had about one million residents. To build by hand the corresponding 7,000 apartment buildings, family houses, public buildings and temples would have taken us forever; but CityEngine's power and flexibility made the process amazingly quick without sacrificing detail or quality. This allowed us to concentrate on modeling the unique monuments. The CityEngine also helps to quickly change the model as new scholarship or discoveries warrant.”

Over 7000 domestic buildings existed in ancient Rome. Since archaeolgical accuracy is of high importance, the street network and the parcels have not be generated with the urban layout tools of the CityEngine. Instead, the reconstruction has to be based on existing and known data, and since no street network or footprints have been available which could have been imported into the CityEngine, rough mass models have been imported.

This resulted in a rather elaborate modeling pipeline. In the first step, the famous Plastico di Gismondi, a huge plaster exhibited and preserved in the Museum of Roman Civilization in Rome, has been scanned under the direction of Bernard Frischer (IATH, University of Virginia) and Gabriele Guidi (Politecnico di Milano). In the second step, the scanned data has been interpreted resulting in  classified mass models available as polygon data. In the last step, these mass models have been imported into the CityEngine.

The modeling pipeline: from Plastico to CityEngine.

In the CityEngine, grammar rules have been designed under the guidance of archaeological consulting. These rules have then be applied to refine the mass models, resulting in detailed 3D building models, which then can be exported into any 3d package or visualisation software.

A building model generated in the CityEngine.

The same building rendered with mental images' mentalray^®.

Since the Rome Reborn project supports different kinds of visualisation and publishing platforms, also different levels of detail have been integrated into the rule set. These levels of detail can either be controlled individually or via global image maps.

On the left, the low detail level with only 167 polygons and alpha maps, on the right the high detail level of the same building with 19800 polygons.

Besides the domestic buildings, the CityEngine has been applied to reconstruct the numerous temples built by the Romans. Ancient temples have been built by following the structured and well-described rules of Classial Architecture. Thus, one grammar rule set has been written which generates Ionic and Corinthian temples. The rule set is highly detailed and contains almost hundred attributes which can be altered to control the final appearance. But often, due to ruination, not all attributes like e.g. the captial height, are known. Therefore, the proportions as described by famous Rennaisance architect Palladio can be easily implemented in the rule set. As a consequence, the user has just to enter the few parameters he knows, the remaining parameters are then calculated proportional to the known parameters.


Ionic temple generated with the CityEngine on a given footprint.

With six attribute changes only, a Corinthian temple with Etruscan podium can be easily generated (on the same footprint).

To summarize, the attributed grammar rule set allows for the accurate parametric modeling of temples. Therefore, and since the CityEngine provides an intuitive user interface for these parameters, the archaeologists can create and alter highly detailed 3D models in very short time.

Level of detail has also been included in the temple rule set, allowing for the generation of temple models with medium and - see picture - extremely detailed high polygon-count.

Rome Reborn exemplifies new approaches for exhibiting historical findings in museums, classrooms, and on the Internet.  Approximately 7,000 buildings recapture Rome at the peak of its glory in 320 AD, at the time of Constantine the Great.  Rome Reborn opens new channels for education,  for collaboration between scholars, and for  the communication of archaeology to the general public.

Several industry and academic partners have collaborated to create Rome Reborn - including  IATH, IBM, Illustrious, mental images, Past Perfect Productions, Procedural Inc., the Politecnico di Milano, and UCLA - each contributing creative content with computer graphics technologies that combine to deliver interactive experiences of ancient Rome.

More information can be found on IATH's Rome Reborn project page.