Real-time droplet modeling using color-space environment matting

Amongst all atmospheric phenomena, rain is probably the most commonly used effect to create realistic immersive virtual environments, and to set the mood in movie storytelling. Although not immediately obvious, the beauty of rain emanates from the interplay of the involved light-matter interaction, generating effects of refraction and reflection, coupled with scattering effects. At the core, rain consists of water droplets under the influence of gravity. Current state of the art methods of generating rain are either computationally burdening, or not realistic enough. The key idea we introduce in this paper is to consider these droplets as transparent objects in the environment matting (EM) framework. This enables careful preprocessing to discover the light transport phenomena. We end up with a free-viewpoint real-time technique of simulating realistic droplets and rain in novel environments.