Modern 3D Laser Scanning Virtually Restores an Ancient Roman Sculpture

For my tenth contribution to LiDAR News over the last year, I believe this submission holds quite true to the reason Gene Roe asked me to be a regular contributor. Quite often my firm, Direct Dimensions uses 3D scanners for interesting applications that are generally different than most readers of this forum. Its essentially the same basic 3D technology, but we apply a different set of tools, software, and skills to different problems.

This article explains how we used other 3D equipment from one of the more common OEMs in the general laser scanning business – FARO Technologies, to capture the intricate geometry of an ancient Roman marble sculpture. Sure, youve read about us and others 3D scanning art and sculpture – modern and historic. But not many 3D projects involve teams of international experts to collaboratively create, review, and virtually repair ancient art with this level of technical and academic precision. Read about the project and view the graphic images linked below to see specifically what I mean. Only one other project comes to mind of this nature, The Digital Michelangelo Project, and as I understand it, they had quite the budget.

Emperor Caligula: A Broken (Marble) Man

The city of Rome is one of the most popular destinations in the world owing to the culture, the architecture, and especially the art that remains from its ancient citizens. Every year millions of visitors visit the travertinestone remains of the Coliseum, the Roman Forum and other amazing sites wondering what life must have been like at the height of the Empire.

Dr. Bernard Frischer of the University of Virginia and the Virtual World Heritage Laboratory employs modern 3D technologies to answer that question. In 2007 he initiated the Rome Reborn project to build a 3D digital version of the original Rome in circa 320 A.D. Today he is directing the Digital Sculpture Project to exploit 3D scanning and modeling technologies for the capture, representation and interpretation of ancient sculpture.

Over the past year, Direct Dimensions worked with Dr. Frischers team to digitally recreate a famous life size marble sculpture of the Emperor Caligula from 1st century Rome. This project resulted in a unique combination of world class 3D technologies with internationally acclaimed academic research.

The Caligula sculpture is owned by the Virginia Museum of Fine Arts (VMFA) and, as one of only two complete existing sculptures of the Emperor, is also considered one of the most important Roman portraits in the United States. While the sculpture is in generally good condition, it suffered damage through the years such as losing its nose and hands, missing chunks of the toga, and a poor repair job some years ago that mis-located his head.

A team of experts from around the world was assembled to research how the Caligula sculpture might have looked like when it was first created. But how would the team collaborate with scientific accuracy on such a large complex sculpture located in Virginia?

The answer: to utilize advanced laser scanning technology to accurately digitize the physical sculpture, thus allowing the team to collaborate virtually in 3D.

Scanning and Reconstructing Caligula

In September 2010, our engineers travelled to the Virginia Museum of Fine Arts where they spent a full day capturing the Caligula sculpture with a laser line scanner mounted on a Faro Arm portable articulating digitizer. They scanned the entire complex piece with an accuracy of about one-tenth of a millimeter and resolution of nearly a quarter millimeter. The resulting 3D point cloud file was over 1.5 GB and contained nearly 137 million points!

Back at the DDI facility in Baltimore, the raw laser data was processed into a super high resolution polygonal model using Innovmetrics PolyWorks Modeler software. For additional technical reference, the final watertight model was nearly 400MB in size and contained over 9 million polygons.

However this exact digital replica model of the existing condition piece was only the first step in our work. The goal for the project was not simply to recreate the Caligula sculpture as it looks today but how it might have looked when it was originally created almost 2,000 years ago. Given its current condition, this meant digitally restoring the missing hands and nose, replacing the missing pieces of the toga, reattaching the detached head and even repainting the sculpture. (Note: while all that we see today is the marble, the ancient Romans actually painted their sculptures in brilliant colors which have worn off over the passing years.)

To perform these tasks, the Direct Dimensions digital modelers worked in close collaboration with the international academic research team to digitally resculpt and repaint the missing elements of the sculpture. Using ZBrush software, for example, our modelers created the shapes for the missing parts such as the hands. The academic experts then indicated how we needed to adjust these hand positions to be representative of the time period. Using those examples exchange digitally across the internet, the DDI modelers were able to iteratively sculpt multiple new versions of the missing components. The research team was then able to suggest edits based on their hypotheses, leading to the creation of multiple digital models. This process was repeated for many of the missing elements and also to help with the positioning of the separated head. After exchanging and studying many iterations, the researchers ultimately selected the final configurations and the project continued to colorization.

When it came time to repaint the digital model, it turned out that very faint traces of the original polychromy (color) still existed allowing the research team to provide a likely color scheme to Direct Dimensions. Again using ZBrush, the DDI modelers created a layering of colors on the digital model which they could turn on or off to display likely depth of color to the academic researchers. For instance, trace findings indicated that part of the toga was once painted purple and the modeler was able to display slightly different purple colors as well as options for an entirely purple toga and also a simple purple sash.

The final digital model was unveiled to the VMFA on December 4th, 2011, during a special symposium entitled Caligula 3D: Man, Myth, Emperor.

Why? Because We Can!

Direct Dimensions is very proud to have contributed its technical capabilities to such an important project. Hopefully more museums and research groups will adopt 3D technologies for similarly important projects. Direct Dimensions has worked with dozens of museums, historic facilities, and academic organizations to bring 3D imaging and virtual digital modeling to the arts. We believe that one day all our worlds art, cultural, and heritage objects will be available to view and interact with by our children on iPads. We started this work a long time ago and we are proving its value every day with projects like this.

To learn more about this Caligula project, please see these links:

Reconstructing Caligula by Direct Dimensions

The 3D Reconstruction of Caligula Slideshow

Caligula Project Image Summary

To learn more about other art and cultural projects, please see these links:

Scanning the Matisses

Reproducting a Rare Darwin Bust

Documenting Ancient Sculptures

To learn more about Direct Dimensions, please see these links:

The Direct Dimensions website, Blog, YouTube Channel, Twitter, and LinkedIn

About the Author

Michael Raphael

Michael Raphael ... Michael earned a BS degree in Engineering Science and Mechanics from Virginia Tech, followed by a Masters of Engineering Administration from George Washington University. During his 10 years at Lockheed Martin as an engineer responsible for solving aerostructures manufacturing quality problems, Michael co-developed the FaroArm portable CMM and became the first user on the planet! In 1995, he founded Direct Dimensions, Inc., providing rapid solutions to 3D problems!

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