Urban analysis often relies on separate geospatial mapping, street-level image analysis, point-cloud analysis and 3D urban modeling workflows, which can lead to semantic and spatial inconsistencies when structural, visual and volumetric results are interpreted together. This paper develops an SPC-guided Smart 3D Gaussian Splatting (S3DGS) analytical framework to address this fragmentation. Using the Aula–library block in Delft as a case study, we construct a CityGML-inspired Smart Point Cloud from laser-scanning data, generate street-level and aerial 3DGS components from multi-view imagery, align and fuse them into a common coordinate frame, and propagate SPC-derived semantics to Gaussian primitives. The resulting S3DGS base supports projection-based semantic composition, observer-centered visual exposure, volumetric spatial-presence aggregation and layered scene typing within the same reference. Cross-layer interpretation links volumetric and visual-exposure types in the same spatial units, revealing conditions such as physically present but visually recessive building mass. This layered reading allows surface composition, visual experience and three-dimensional spatial presence to be traced within the same urban unit. Evaluation results indicate a stable workflow, with an alignment RMSE of 0.0439 m and a kNN label consistency of 92.24%. By turning Gaussian scenes into semantically traceable and spatially co-referenced analytical bases, S3DGS offers a practical pathway from isolated urban measurements toward integrated, viewpoint-aware and three-dimensional interpretation of the built environment. ... Read more

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. ... Read more

Incremental urban and community expansion in rural heritage landscapes often produces cumulative visual impacts, yet planning rarely specifies a clear endpoint for acceptable change. This paper proposes an integrated Visual Impact Assessment (VIA) framework, aligned with SDG 11, to determine “when to stop” using stage-comparable evidence across past, present, and future conditions. The framework is organized in three modules. First, a point cloud-enhanced GIS module quantifies visibility and spatial change across development stages. Second, an enhanced Key Observation Point (KOP) module derives matched eye-level evidence from multi-temporal street-level panoramas and scenario visualizations, for example using Street View Imagery (SVI) time series and 3D Gaussian Splatting (3DGS) rendering. Third, a decision layer integrates structured public acceptability from a questionnaire covering different respondent groups with in-depth expert interviews and synthesis, with virtual reality (VR) eye- and head-tracking used as supportive behavioral evidence. Applied to the Middenbeemster expansion in the Beemster Polder, the Netherlands, the framework yields a case-calibrated reference package for decision support: KOP-based construction intensity serves as the primary reference line for review, perception indicators serve as supporting guardrails, spatial character metrics act as case-specific reference checks to protect the polder framework, and visibility diagnostics remain a necessary screening layer. More broadly, the framework provides a transparent and replicable procedure that can be transferred and locally recalibrated for heritage-sensitive rural-urban fringes where change is incremental and cumulative, supporting a stage-comparable VIA approach. ... Read more