Bridging Spatiotemporal Scales: A Hybrid Web3D Framework for History Education

Web3D technologies enable global access to cultural heritage, yet online digital museums struggle to present vast macroscopic contexts alongside high-fidelity artifacts without disorienting users. We propose a lightweight Web-based visualization framework that bridges 2D spatiotemporal maps and 3D inspections through a dual-camera finite state machine and a "render-to-texture" visual anchor. This anchor projects the macro-context into the 3D space, preserving spatial cognition during seamless transitions. A prototype, "The Digital Silk Road," is implemented using HTML5 and WebGL. A within-subjects user study ($N=24$) shows the framework reduces navigation errors by 55% and task time by 32% (Cohen's $d \gt 1.3$) versus traditional click-and-load designs. Technical benchmarks confirm 78-88 FPS on consumer hardware with negligible overhead. The system aligns with IRVE theory, maps to X3D standards, and offers a scalable solution for presenting heterogeneous heritage data on the Web.