Enhancing the Interpretability of 3D City Model Validation Through Web Visualization: The Case Study of the CHEK Validation Results Viewer

3D city models (3DCMs) are increasingly used in urban simulations, cadastral workflows, and digital building permit processes, and automated validation of these models has become a routine requirement. Existing validation services typically produce dense, frequently generated by SHACL engines, text-based reports that are difficult for users without a semantic-web background to interpret. This paper describes the CHEK Validation Results Viewer (CHEK VRV), a Flask-based web application that couples the OGC Data Completeness Validator with an interactive Three.js 3D viewer of the CityJSON input. SHACL violations and geometric invalidities are spatially explorable on a visual representation of the model, and the tool supports both predefined CHEK Building Block Profiles and user-uploaded custom profiles. We report a formative usability study with twelve domain experts (urban planners, data vendors, academics) and use it to identify the tool’s current strengths, its limitations, and a prioritized development roadmap. As reported by the participant experts, such a presentation is easier to interpret than the raw JSON-LD report.