Medieval goldsmithing put to the test of digital modeling.
eThesaurus is an art and technology history project led by a team of French and Belgian academics, museum curators, and Holusion, a specialist in innovative digital display.
eThesaurus
Broadcast eThesaurus modeling results
The project involves the digitization of six medieval goldsmithing works: :
Three works held at the Sandelin Museum in Saint-Omer:
- Foot of the cross of Saint-Bertin abbey (v. 1170-1180)
- The True Cross reliquary cross, from the Abbey of Clairmarais (v. 1210-1220)
- A pedestal pyx or box for consecrated hosts mounted on a stand (v. 1220)
In a second phase, three other pieces, held at the Palais des Beaux-arts in Lille, were modeled in the spring of 2020:
- The Wasnes-au-Bac reliquary cross (v.1220-1230)
- The Gideon Plate (v. 1160)
- The Hebrews' Censer (v. 1170)
Digitization
The digital models resulting from photogrammetry capture include information related to the object's geometry in the form of a mesh, as well as information related to its visual appearance described in a PBR (Physical Based Rendering) model, which describes the optical properties of each point on the object, such as color, reflection, specular highlights, roughness, etc.
This information is sufficient to create video animations, particularly in the case of Holomouseio, to display a digital replica of the object.
Viewing and Editing in 3D
Editing tools for researchers and conservators
eCorpus is a database of 3D models that uses DPO-voyager as a 3D viewer and metadata editor, a modification history manager, a user rights manager. It also provides application management tools to install it on a local server.
Open source
The development results are distributed under an open source license, allowing the user to fully own their data and environment.
Decentralized
The application architecture works through the deployment of independent instances, with databases being compatible with each other but entirely separate.
Browser-accessible
Web technologies are currently the only ones offering a wide range of distribution opportunities. The requirement of developping an application for each possible consummer type would be considered a major obstacle.
Indexable in databases
Most use cases involve entities that already have a content management solution, such as OMEKA S. eCorpus data can be integrated and searched within it.
Documented and equipped with a collaborative development environment
The dynamism of an Open Source project is crucial to its success and distribution. Its documentation is available on a platform like GitHub and there is regular development activity with a clearly identified team.
eCorpus
eCorpus incorporates tools for the enhancement of a 3D catalog, collaborative analysis and research tools, as well as export options for use in museum or educational settings.
Its primary function is to allow data to be directly linked to an object and its geometry through enriched annotations. These annotations combine a title, an abstract, and an article that may contain multimedia content (videos, images, links...) in enriched text (HTML).
The metadata for each entry in the database is organized into a reference JSON file, with linked files (3D object, textures, articles, images, videos, etc.).
This organization allows for great flexibility: the exported data can be used independently of the server on which it is stored.
The file describing the scenes enables management of models with multiple levels of detail (LOD), as well as translation of the various metadata.
Each entry in the database can therefore be composed of an assembly of sub-elements, and each of these sub-elements may contain multi-resolution models that offer optimized loading of geometry by the client, limiting the loading of complex data according to its needs.
Alternative models offer different visualizations of the model through distinct captures, for example, in non-visible light or through radiography.
These 3D models also allow for storing data related to their animation. This step of storing movement information is important for mechanism simulations such as clocks or complex assembly/disassembly demonstrations.
All this information, these models, and their animations can be animated through "Tours" within the platform. A tour allows the user to simply set steps in the visualization while letting the software interpolate movements from one point to another. They can determine key animations, disassembly of a system, or light management.
Mediation and distribution of content
eCorpus allows for the distribution of 3D objects and metadata in two different configurations.
On one hand, the integration of the Voyager viewer in a webpage or application allows for direct access to the latest version of the 3D object from the server, depending on the user's distribution rights.
This is the simplest method for presenting results on institutional websites, via email or mobile applications.
The latest developments in terms of Augmented Reality also allow for direct distribution of the object in this format through Apple's AR Kit 8 or Android without the need for a third-party application.
In some use cases, particularly for installations in museums or exhibitions outside of traditional venues, an internet connection may not be available.
In this regard, it is possible to create applications that work with a local database exported from the online platform. This allows for asynchronous work and the addition of data over time, before exporting for use in a mediation context in an exhibition space.
Among the different export formats for mediation, eCorpus supports visualization on touch tables, mobile tablets, holograms, and virtual and augmented reality devices.
The eThesaurus demonstrator, manufactured by Holusion, allows for the visualization of an eCorpus database export.
The display is split across two screens. The transparent screen is dedicated to the visualization of 3D objects, animations, and concise annotations.
Navigation is provided by a secondary screen placed in front of the device. Touch control was chosen for its prevalence among audiences, accustomed to using smartphones and tablets on a daily basis.
On this screen, the user can consult textual information and complementary photo and video media included in the articles.