Sky illumination is a core source of lighting in rendering, and a substantial amount of work has been developed to simulate lighting from clear skies. However, in reality, clouds substantially alter the appearance of the sky and subsequently change the scene's illumination. While there have been recent advances in developing sky models which include clouds, these all neglect cloud movement which is a crucial component of cloudy sky appearance. In any sort of video or interactive environment, it can be expected that clouds will move, sometimes quite substantially in a short period of time. Our work proposes a solution to this which enables whole-sky dynamic cloud synthesis for the first time. We achieve this by proposing a multi-timescale sky appearance model which learns to predict the sky illumination over various timescales, and can be used to add dynamism to previous static, cloudy sky lighting approaches.

翻译：天空光照是渲染中的核心光源之一，大量研究工作已致力于模拟晴空光照。然而实际场景中，云层会显著改变天空外观，进而影响场景照明效果。尽管近年来已有包含云层的天空模型研究进展，但这些模型均忽略了云层运动这一关键要素。在各类视频或交互式环境中，云层必然产生移动，有时会在短时间内发生显著位移。本研究首次提出解决方案，实现了全天空动态云合成。为此，我们提出多时间尺度天空外观模型，该模型能够学习预测不同时间尺度下的天空光照，并可为先前的静态多云天空光照方案赋予动态特性。