Oz: the great and volumetric

Path traced volumes in production Starting on The Amazing Spiderman and Men In Black 3, Imageworks’ in-house version of Arnold has supported path tracing of volumes alongside surfaces. The pipeline is built around the Field3D file format, and volume primitives support all standard light sources, including area lights and textured skydomes. We maintain reasonable render times with the importance sampling techniques detailed in [Kulla and Fajardo 2012]. To lighters, volumes were seen as just another scene graph location in Katana, with a geometric proxy representation for fast previewing and layout. Named attributes of each field automatically bind to similarly named shader parameters, so that TDs can write custom shaders easily. Under the hood, the Field3D primitive supported arbitrary numbers of fields in each .f3d file, and had full support for dense, sparse and MAC fields of mixed bit depths.