The Hemisphere Skies plugin for Unreal Engine was designed to create high dynamic range (HDR) time-lapse skies and realistic environmental lighting.
The plugin integrates seamlessly with Unreal Engine’s native lighting and fog components, supporting extended luminance range workflows to achieve realistic lighting conditions based on physical lighting units.
It uses a 180-degree fisheye lens to capture images every 5 seconds of the top half of the surroundings (the skybox). These images are processed into HDRI SkyLight cubemap and skybox textures. For the skybox, OpenCV is employed to create Optical Flow Estimation textures, which facilitate the interpolation between pixels of two different images, resulting in smooth skybox transitions.
The plugin also utilizes data from a solar intensity logger to provide accurate cd/m2 and lux values for realistic scientifically correct scene lighting for PBR.
Additionally, it offers full sequencer support and an intuitive user interface, resulting in a seamless integration within the Unreal Engine editor.
Development and Impact:
The plugin aimed to enhance environmental realism in game development and simulation projects by incorporating real-life HDR sky recordings and advanced lighting techniques and has been used in architectural visualization projects as well as shipped games.