False-Colour Map for Luminance Distribution Visualisation in Unreal Engine

Abstract

Virtual reality and game engines are increasingly employed as tools for architectural lighting design and analysis, enabling immersive and quantitative evaluation of light distribution in virtual environments. Unreal Engine 4 (UE4) has demonstrated the capability to reproduce accurate light distributions when light sources are properly calibrated. False-colour maps of luminance values are among the most widely used outputs in lighting design, as they allow rapid visual assessment of light distribution quality. However, the integration of such visualisation tools directly within a game engine rendering pipeline remains limited in the literature. This paper aims to develop and present a false-colour luminance visualisation system fully integrated within the UE4 rendering pipeline, capable of providing real-time spatial luminance visualisation directly within calibrated virtual environments. The system captures the rendered scene in high dynamic range, extracts luminance values for each pixel, and maps them to a colour scale. The visualisation operates directly within the game engine, before any image processing is applied, ensuring that the colours displayed reflect the actual light levels in the scene. The system also responds automatically to changes in lighting configuration, updating the colour scale without any manual input. To validate the approach, the same environment was modelled in DIALux evo and luminance values at reference points in both software were compared. The results indicate that the generated false-colour visualisations accurately reflect the luminance distribution of the scene. The proposed system provides an integrated, real-time false-colour luminance visualisation tool for virtual environments in UE4, facilitating a more comprehensive analysis of luminance across the rendered scene. The approach offers a practical framework for lighting designers and researchers and establishes a foundation for future extensions including wider scene coverage and integration with immersive VR workflows.