What to do about streaming? -Jocelyn
The Visionary Cross Project has been investigating streaming options for the three full models of Old English monuments (the Ruthwell Cross, the Bewcastle Cross, and the Brussels Cross) since September 2024. Over the past eleven months, several approaches have been tested. This report provides an overview of the possible streaming solutions and the project’s involvement with each.
1. Wiki-Based Solutions
Wikis are flexible for categorization and entries and allow the addition and reconnection of material without negotiation. However, they do not preserve authority, they require ongoing maintenance, and they provide only one form of presentation. Most importantly, they are not effective for displaying 3D models.
2. Game Engines
Game engines offer different ways of organizing materials and are effective for object and collection management. They also preserve authority, and some engines support external contributions. However, they require others to adopt our system, they offer limited opportunities for external contributions, and they require ongoing maintenance. Displaying the 3D models would be relatively simple if this framework was used.
3. OPenn
OPenn provides a lightly skinned directory structure that is both human- and machine-readable. It can display groupings, focus on individuals or collections, extract data from systems, and preserve authority. It also requires no software maintenance.
However, OPenn has a rigid hierarchical data structure, additions or reorganizations require server access, and publishers are responsible for server maintenance. Like wikis, it does not provide a suitable solution for displaying 3D models.
4. Zenodo and GitHub
Zenodo guarantees preservation, assigns DOIs, and supports rich metadata. GitHub provides version control, collaboration, and publishing. By linking GitHub repositories to Zenodo, they become archived in Zenodo, producing citable versions.
This is the method currently pursued by the Visionary Cross Project. However, the challenge lies in streaming 3D models:
• Models cannot stream from Zenodo to GitHub, as this feature is not supported and will not be added.
• GitHub imposes strict size limits: 100 MB per file and a total repository size cap of 5GB.
The Ruthwell Cross master model is 2.5 GB, and the Bewcastle Cross master model is 4 GB. This makes the models 25–40 times too large for GitHub. To reduce them to the required size, millions of polygon faces would need to be decimated to thousands, resulting in severe loss of detail and texture.
By contrast, individual panels of the crosses are about 100 MB each and could be hosted on GitHub with 3DHOP, making them more practical for access.
5. Archaeological Data Service (ADS)
The ADS offered a system that could support the framework of the project, especially as the Las Cuevas Project (hosted on the ADS since 2015) demonstrates a close alignment with the desired model for the edition. ADS also operates its own servers for streaming and employs a dedicated team for maintaining models and metadata.
Despite this, ADS no longer provides public project displays comparable to what the Visionary Cross Project requires. When asked about streaming to the GitHub/Zenodo edition, ADS indicated that it is not something they normally allow, but they would consider it if the project could provide an estimated usage number, as heavy use would impact their servers.
The Visionary Cross Project has until the end of summer to respond to ADS.
6. IIIF (International Image Interoperability Framework)
ADS suggested IIIF as a potential future solution. If the models were hosted with IIIF technology, the Visionary Cross Project could implement an IIIF viewer in the edition and link directly to the models. This option may become available next year.
7. Other Options
Other hosting and streaming options have been explored:
• University of Lethbridge systems (OPUS and Borealis) were evaluated, but communications with both services confirmed they would not meet the project’s needs.
• Commercial and open repositories such as Dropbox, Open Science, Dataverse, and Figshare were tested but proved unsuccessful for streaming models into GitHub.
