Trompe-l'oeil of the Forum of Caesaraugusta
Ayto. de Zaragoza
The requirementes
The Caesaraugusta Forum Museum is located in a unique building in the center of Saragossa, next to the heterogeneous Cathedral of La Seo, undoubtedly one of the most beautiful and most interesting architectural and heritage sites in Spain.
In this context, the city council asked us, through the Municipal Museum Service, for a very special project: to recreate the ancient Roman Forum in such a way that different views of it could be integrated into the huge windows of the museum, thus giving the passer-by an idea of what he could have admired from his own point of view, in the past (2nd century BC) of Caesaraugusta.
There was also one last requirement for this project. The intervention had to harmonize with the existing museum building, without being so conspicuous as to rival its architecture. In addition, the 3D images had to be visible both from the outside of the museum and from the inside and, as if that were not enough, allow the viewer to look through them, allowing them to fix their gaze on the printed image or to focus their gaze further away to admire the square behind the images.
Our approach
The aim of the project was clear. It was none other than to give passers-by the sensation that, through the museum's windows, they could look out onto the Roman forum of the 2nd century BC.
We were therefore talking here about implementing a technique already known since the beginning of humanism, in 15th century Florence: the trompe l'oeil. Literally "trap before the eye".
This artistic technique tries to achieve the integration, as refined as possible, of a flat visual element in the real architectural environment. To achieve this, it is necessary to deceive the eye, taking advantage of the illusion achieved thanks to perspective, shading and other optical aspects. This is a kind of primitive Augmented Reality.
Thus, in our case we had to achieve this effect of visual continuity between the real architecture of the building, the existing buildings in the square and the perspective of the retrospective images, generated from a 3D scene.
We started the project by generating the virtual images. In VÓRTICE we had made years ago a series of audiovisuals about the Roman Saragossa, creating for it the 3D models of the ancient Forum of Caesaugusta.
We completely updated the 3D scenes using modern PBR (Physically Based Rendering) shading techniques. For this we reworked all the textures used, because at the time the models were created to be displayed in Full HD 1080p video, and this new project required RAW images of more than 10,000 pixels resolution, on its longest side.
With the arduous task of reconstructing the model of the Forum now complete, we moved on to recreate in 3D the facades of the actual museum building. With this we could place the camera at the height of a viewer looking through the museum windows, to see the Forum in its correct scale and geoposition.
Together with the technical experts in heritage of the City Council we chose the points of view, squaring the perspectives, and we composed the frames including people in 3D and other elements such as fog to create a more vivid feeling. As for the lighting we opted for a diffuse light without hard shadows, in order to achieve the best integration with the museum building, with any time of day and weather.
The next step was to render the images by sections, in different passes or layers that allowed us to compose and adjust the photographic levels of the final image.
North view of the Forum of Caesaraugusta (© VÓRTICE)
South view of the Forum of Caesaraugusta (© VÓRTICE)
With these virtual recreations in image files, we were clear that the support where they had to be printed would be the vinyl, so we proceeded to perform a battery of printing tests, exploring different techniques and modifications of the support.
The first considered option was the micro-perforated vinyl, printed on both sides and placed on the outside of the glass, which is undoubtedly the best way to appreciate the color and contrast of the image, but it is exposed to inclement weather and vandalism. In addition, it was too prominent on the façade of the museum and was therefore rejected.
Aspect tests with outdoor vinyls
For this reason we turned to Femonsa, specialists in all types of special signage, looking for options that could be placed on the inside of the glass. The tests pushed the possibilities offered by the support and the skill of Femonsa's technicians to the limit, even combining laborious processes that had not been tried before.
Finally, the museum managers opted for the micro-perforated supercrystalline vinyl placed on the inside, printed on both sides with a succession of black and white background layers, in order to enhance the colors of the image, both on the outside and inside.
Aspect tests with indoor vinyls
From that point on, as if it were a huge puzzle, the images, almost 13 meters long by 2.5 meters high, were printed in sections.
After that, the vinyls were installed over the course of several days. It was necessary to dismantle part of the museum's furniture to access the windows and to be precise in matching all the different sections in their corresponding places.
The result
It cannot be denied that the desired visual effect has been fully achieved. All this after arriving at a solution that we find really elegant, allowing the printed image to be seen in the opaque part or, if desired, to look beyond through the holes in the micro-perforation.
To bring you closer to this undoubtedly very interesting project, we wanted to prepare the following "Making of", with which we invite you to learn about this interesting project and, at the same time, to the Museum of the Forum of Caesaugusta.