OntoHistArch provides the vocabulary to (1) describe the architectural historical research of historical buildings as a knowledge graph. This includes the collection and addition of source material (metadata) and of scientific interpretations by the researcher (paradata)(2) link the resulting hypothetical 3D reconstruction to the knowledge graph of this architectural historical research. To use the vocabulary, step (2) is optional and complements step (1), but it is not mandatory. In other words, architectural historical research can be conducted and documented using OntoHistArch without creating a 3D model. For more information on the methodology:"A Methodological Framework for Transparant, Data-Driven historical 3D Reconstructions, enriched with Machine-Readable Metadata and Paradata" by Van Meerbeek & Maekelberg (2025), published in Digital Humanities Quarterly.