The digital turn within both the sciences and humanities has facilitated the (re)creation of lost or never-built architectural and urban heritage as digital 3D models. Source-based hypothetical 3D reconstructions allow researchers to visually narrate a building’s history and present complex data in an accessible format. However, the absence of standardised methods for documenting, publishing, and preserving these models has led to the production of numerous outdated, unreadable, or unusable datasets within the cultural heritage domain.

This doctoral thesis addresses five critical phases in the lifecycle of digital 3D assets (Fig. 1):

1. Planning, which involves selecting reconstruction strategies that align with the historical context, available sources, and intended research outcomes (Fig. 2);
2. Creation, focusing on systematising modelling methods, tools, and documentation practices, illustrated through case studies such as the synagogue in Speyer (1250) and the St. Johannis Church in Mainz (800).
3. Publication, which evaluates online repositories (Fig. 3), metadata standards, and the integration of Semantic Web technologies to enable interoperable and structured data representation;
4. Reuse, which addresses the adaptation of models and their metadata to comply with the FAIR Principles and Linked Open Data frameworks (Fig. 4). This includes analysis of file formats commonly used in the 3D graphics (e.g., OBJ, DAE) and architectural communities (e.g., CitGML, IFC), focusing on their potential for encoding geometric, semantic, and contextual information.

The final phase of the research involves the design of a tailored ontology for documenting digital 3D reconstructions (OntPreHer3D) based on the CIDOC CRM (Fig. 5). This ontology will formalise concepts and relationships specific to source-based reconstructions. It will be implemented into a WissKI-based semantic web environment. The resulting system will serve as a prototype for a sustainable, open-access digital 3D repository, designed to support the educational, scientific, and preservation needs of the cultural heritage community. By addressing the full digital lifecycle and proposing a standards-based infrastructure, this research contributes to resolving key barriers in 3D heritage documentation, publication, and reuse, making digital heritage more accessible, transparent, and enduring.