The second workshop on metadata for 3D cultural heritage was held on March 29, 2023, during the UHDL Conference. Organised within the framework of the DFG 3D-Viewer project, the event continued the discussion started in Mainz (2022) on how to document, describe, and share 3D models of cultural heritage in a consistent and interoperable way.

Following the first edition’s focus on mapping existing documentation schemas, this workshop explored how 3D models can be aggregated across repositories and which metadata fields are essential to make them accessible, reusable, and scientifically transparent. Participants discussed how metadata can support both academic research and long-term preservation, while enabling interoperability with platforms such as Europeana or the Deutsche Digitale Bibliothek.

Key discussion points included:

• Defining a minimum metadata set for identifying and interpreting 3D models;
• Expressing rights and copyright information in a consistent way;
• Describing processes and provenance as part of 3D documentation;
• Integrating georeferencing and spatial data for architectural models;
• Aligning technical and descriptive metadata to support aggregation.

The outcomes highlighted the importance of a layered approach to metadata, distinguishing between core and extended elements, and the need for shared vocabularies and persistent identifiers to ensure interoperability. The workshop’s findings were later summarised and published in the UHDL 2023 Proceedings as: Bajena, I., & Kuroczyński, P. (2023). Metadata for 3D Digital Heritage Models: In the Search of a Common Ground. In: Münster, S., Pattee, A., Kröber, C., & Niebling, F. (eds) Research and Education in Urban History in the Age of Digital Libraries. UHDL 2023. Communications in Computer and Information Science, vol. 1853. Springer, Cham. https://doi.org/10.1007/978-3-031-38871-2_4

All results were documented on a shared Miro board, expanding the collaborative reference created after the first workshop in Mainz. These findings laid the groundwork for the third edition (Bielefeld, 2025), which continues to develop a core metadata schema for 3D model documentation and aggregation.As in previous editions, the discussion outcomes will be documented on the same Miro Board, contributing to an expanding compendium of knowledge.