Visualizing building interiors using virtual windows

The feature film "Big Hero 6" is set in a fictional city with numerous scenes encompassing hundreds of buildings. The objects visible inside the windows, especially during nighttime, play a vital role in portraying the realism of the scene. Unfortunately, it can be expensive to individually model each room in every building. Thus, the production team needed a way to render building interiors with reasonable parallax effects, without adding geometry in an already large scene. This paper describes a novel building interior visualization system using a Virtual Window Shader (Shader) written for a ray-traced global illumination (GI) multi-bounce renderer [Eisenacher et al. 2013]. The Shader efficiently creates an illusion of geometry and light sources inside building windows using only pre-baked textures.