Towards the architectural heritage information infrastructure: a UML-based information model linking HBIM, smart point clouds, and 3D Gaussian splatting

This paper presents the Architectural Heritage Information Infrastructure (AHII), a standards-operational framework for maintaining identity, semantics, and traceability across three complementary representations used in heritage workflows: Smart Point Clouds (SPC), HBIM/IFC, and Smart 3D Gaussian Splatting (S3DGS). AHII is centered on a compact UML information model and governed code lists, and it operationalizes cross-representation continuity through a shared alignment transform and an explicit identifier crosswalk. This design supports task-driven switching between evidence-grade inspection (SPC), standards-based querying and exchange (IFC), and lightweight photorealistic dissemination (S3DGS), while maintaining auditable correspondence across iterative updates. We validate AHII on two Dutch case studies using a reproducible protocol with fixed evaluation splits and independent checkpoints, complemented by an online, task-anchored user study (N = 200). Results provide evidence of cross-representation interoperability, together with task-appropriate technical performance: intrinsic SPC segmentation reaches macro-mIoU ≈ 0.88, cross-representation co-location achieves 3D RMSE on the order of 1–3 cm, and IFC4 round-trip checks preserve GUIDs with near-lossless property-set retention. Together, these findings show that AHII can be implemented in practice as a traceable information infrastructure linking documentation, modeling, standards-based data and semantic exchange, and dissemination across heterogeneous representations.