BIM-Based Assessment of Light-Transmitting (Translucent) Concrete: Methods, Calibration, and Design Applications

Abstract

Mainstream BIM lighting engines cannot model micro-scale light piping inside plastic optical fibers (POFs), which makes literal fiber geometry visually convincing but metrically unreliable. We propose a pragmatic dual-model workflow that separates appearance from analysis: (1) a detailed fiber-optic wall family for architectural visualization, and (2) a homogenized composite material whose visible transmittance (VT) is set directly from laboratory lux-based transmittance tests. We document a reproducible calibration recipe—project location and weather (GHI/DNI/DHI), validated sky model, realistic glazing VT and surface reflectances, analysis-plane height, grid density, and reporting thresholds—and show how to map measured to BIM VT. A building-scale case study (Baghdad, Perez all-weather sky) demonstrates that the calibrated model reveals under-lit cores and over-bright perimeters, guiding strategic placement of LTC/POF elements to improve illuminance uniformity while reducing reliance on large vision glazing. We discuss limitations (directionality, thickness effects, solver simplifications) and outline research needs, including BIM–optical co-simulation and a standardized “calibration dossier.” The contribution is a clear, repeatable pathway from laboratory transmittance to decision-grade BIM predictions for LTC in real projects.