Holograms

Ralph Breaks the Internet provided a new challenge of rendering holographic objects. Our typical approach to transparency would not be appropriate as we did not want the internal structure of holograms to be visible.

Creating a new hologram shader feature allows rays to skip sets of geometry after emitting light at the first surface intersection and calculated the next continuation point beyond the object, avoiding shading events at intermediate points. We wanted to add an "edge glow" which required the shader to compute an estimated distance to the object silhouette in a manner that would robustly support reflections and efficiently integrate in a path-tracing framework. These extensions provide the flexibility and user control that allows artists to achieve the desired hologram effects for our film.