Create 3D content that is as true historically as possible is a very complex task, especially if your target is VR. As an example I will show you the process that I followed with the Arch of Septimius Severus.
The Arch of Septimius Severus is one of the few elements that remain fairly intact in the Roman Forum, together with the Curia Julia. It is 25 meters wide by 23 high and nearly 12 deep. It was built by the emperor of the same name in 203 to glorify the victories won by him and his sons Geta and Caracalla against the Parthians.
The dedication that is engraved on the facade has also reached us very well preserved, although the amended by Caracalla to remove the mention of his brother Geta, that nonetheless has been deciphered by observing the marks of old letters. Originally, this inscription must be made with bronze letters.
Inside the support located south, a ladder can climb to the top, where there was a today impractical terrace balcony. As has been discovered by ancient coins, the summit was crowned by a fabulous quadriga of six horses, led by Emperor Septimius and the goddess Victoria, flanked by statues of Geta and Caracalla, and in the corners by equestrian statues, forming an impressive sculpture. None of this has survived today.
On the sides of the arch facade bas-reliefs are made with scenes of the most prominent battles. On the Capitoline side are the best preserved. The left panel depicts the city of Seleucia under attack, its eventual fall, and defeated Parthians. The right panel shows the siege of Ctesiphon with its ultimate defeat and Septimius Severus speaking in front of his victorious army. On the Forum side, the left panel shows the army leaving their camp, a battle, Septimius Severus speaking before his troops, and the liberation of Nisibis. The right panel shows siege machines attacking the city of Edessa, a group of Parthians surrendering to Septimius Severus, a war council within a fortified camp, and the launch of a new campaign.
Many decorative elements fill the facades, as reliefs of the Victory and river gods in the spandrels, or reliefs of captives led by Roman soldiers surrounding the pedestals of the columns.
Recreate the Arch has taken me quite longer than expected even though the entire building exists today and that its shape and dimensions are known. The problem has been how to recreate the reliefs and the multitude of details that these Roman constructions used to have.
For reliefs, my original intention was to use current photos of the reliefs. The problem is that the reliefs are badly damaged, with many headless bodies and pieces of sculptures incomplete. In addition, a current photo is of little use to then extract the relief. The reliefs are dirty and with moisture bands caused by the passing years. That would result in a bump mapping that are detected as shadows deeper things that are not.
I was about to give up doing much more than glue pictures as textures, when I found on the Web extraordinary photos of the reliefs, but in perfect shading. Where were these pictures from? After much searching I found that in the Civilta Romana Museum in Rome, there is a scale reproduction of the arch, with all the reliefs reconstructed by the expert hand of a sculptor. Even at scale, the detail of the reliefs are amazing, and some photos of this papier mache reconstruction are almost as detailed as a picture of the actual monument, with the bonus that have no trace of spots or strange shadows. Further evidence of the enormous difficulty that historical reconstruction has. Recreate the reliefs with fidelity not only would have required a collection of studies on how archaeologists think the relief might be in its original version undamaged, but in 3D, that would mean modeling using a sculpting tool as ZBrush, and hundreds of hours of modeler. And we have plenty of reliefs on the monument, each different and unique, with very little repetition or patterns.
What’s more impressive is that Google has launched a project to map the interior of all museums in the world, the Art Project , and curiously museum Civilta Romana is one of them. One can walk around the halls and see the models and recreations of this great Rome museum, including macro model of Rome made of plastic, Plastico Rome Antico , made by architect Italo Gismondi, a monumental work, biggest miniature recreation of imperial Rome. And what’s more amazing is that the project can be followed on Google Google Maps. For example, if you want to move to the Museum to see the model of the Arch of Septimius Severus just you have to click here.
The creation process of reliefs has been simplified a lot to me thanks to this discovery. Now I could take pictures of the model (taken from the Internet, because the Google Art Project didn’t let me take some good quality photos), and with a little work in Photoshop, cleaning and editing photos, get reliefs that look like an AO (ambient occlusion), so I could generate a normal textures and bump mapping much more acceptable.
For the sculptures of the summit, the issue is even more complicated because we do not have any of them, has not been a trace. Model a chariot with six horses and several people is also a daunting task of hours. How to do it without put there a huge time needed to rebuild also many other parts of the Forum? The only options available are to search for 3D models created by others and purchase or use free 3D models that are being shared on websites. For me it was a discovery the MyMiniFactory webpage, that lets you download 3D models created from real sculptures by photographic techniques. Of particular interest is the project Scan the World , where every day great detail 3D models of classical sculptures are been shared, a valuable source of 3D models to be used as an example and base for sculptures in projects like this to recreate Rome in VR. 3D models of this web have an enormous amount of triangles, are highpoly models, but can be simplified using decimation techniques or using retopology software as Topogun . The huge advantage is that we avoid the big amount of hours required using only photographs and modeling on top and using sculpting tools. Moreover, as models are highpoly, we have all the baking of the details already done. The truth is that this technique of using photogrammetry to recreate a 3D model from an existing sculpture rather than shape it by hand is a technique that is often used when there is already an existing model. Many large videogame studios or animation facilities use it for the time savings it represents.
The end result is something like what I show here. An arch of Septimius Severus pretty close to it was in its time, and that has suppose only a week of work in front of what could be several months of an artist who did not use any work done by others and had to model everything from scratch.
This gives a sample of the enormous work involved in recreating historically a place in a game-engine. It involves the use of historical documentation of previous recreations of other artists, and finally go to the graphics engine in real time. A whole lot of techniques that often end up being just a screenshot in a magazine or on a screen. However, VR let us appreciate more the work. Now you can pass under the virtual arch and approach it to see more detail in the reliefs, something that before, looking only at the screen, was not possible. That’s something encourage to continue working of this kind of stuff because the degree of enjoyment you have from a historical recreation is about ten times what a video allow in a typical documentary about History.