Real-time Volumetric Cloud Visualization of Meteorological Simulation Data

Notes: This archive contains a cyclone simulation as png/csv files and as Unreal Engine 4.27 assets. Documentation can be found in the linked git repository. Abstract: I present a concept for visualizing realistic volumetric clouds in real-time in the Unreal Engine using a scientific weather simulation as a basis. From the simulation files, I extract and compress non-linearly spaced variables such as cloud density, rainfall, and wind speed. Cloud density is used as the basis for ray-marched volumetric clouds in Unreal Engine. The clouds use wind speed as a flow map and rain density as a color map. I add Voronoi noise to the clouds and mask it with wind speed to add dynamic detail. I am also able to animate all time steps of the simulation in real-time. A user study shows that most of the added effects improve realism and my implementation is five out of six times more realistic than previous methods. The median performance of a playable prototype on consumer-grade hardware is 128~FPS and meets the performance target.

备注：本归档文件包含以PNG/CSV格式存储的气旋模拟数据，以及虚幻引擎4.27（Unreal Engine 4.27）可用资源。相关文档可在关联的Git代码仓库中获取。

摘要：本文提出了一种以科学气象模拟为基础，在虚幻引擎中实时渲染写实性体积云的方案。研究人员从模拟文件中提取云密度、降雨量、风速等非线性分布变量，并对其进行压缩处理。以云密度为基础，在虚幻引擎中通过光线步进（ray-marched）技术生成体积云；该体积云以风速作为流动贴图、降雨密度作为颜色贴图。此外，为体积云添加沃罗诺伊噪声（Voronoi noise），并通过风速对噪声进行遮罩以增添动态细节。本方案还支持对模拟的所有时间步长进行实时动画渲染。用户研究结果表明，多数新增效果均能提升渲染写实性，且在六组对比中有五组，本实现的写实程度优于此前方法。在消费级硬件上运行的可游玩原型中位帧率可达128帧每秒，符合性能目标要求。