matrinerox.blogg.se - Renderman materials tutorial

#RENDERMAN MATERIALS TUTORIAL UPDATE#

Transmit Specular: TT light transmits through the hair surface (forward scattering) and produces the important back lighting.

Secondary Specular: TRT “transmit” this becomes the colored specular contribution.

Primary Specular: This can be described as the specular reflection.

The success of the Marschner model is in great part due to the specular estimatation and it’s deployment of three specular lobes using multiple specular transport paths: We spoke to both Professor Steve Marschner at Cornell University and Christophe Hery at Pixar Research group about the evolution of Pixar’s PxrMarschnerHair solution. The primary Marschner model has been optimised and extended by the Pixar Rendering Research Group from the initial paper published in 2003 by Steve Marschner et al : Light Scattering from Human Hair Fibers.

(Model and Groom by TELYUKA created with Maya, Shave and a Haircut, & RenderMan (see also our Saya story on Telyuka)). The advanced hair model is innovative for its complex backscattering and glint and when it was released in RenderMan 19, it was the only commercial renderer that offered those features. The Marschner Hair shader was first released in RenderMan 19 and it has been improved for the newest release 21.5. Believable hair adds not only realism but production value and key character personality. This remarkable work has been both significant and enormously impactful.

#RENDERMAN MATERIALS TUTORIAL UPDATE#

A major milestone in RenderMan’s hair solution was the addition and subsequent update of the Marschner Hair shader.

Hair is a key factor in so much of Pixar’s character work. Pixar has long needed to be able to produce CG hair for film’s such as Monsters University, Good Dinosaur, Finding Dory (the seals) and many others. Good Dinosaur was the first use of PxrMarschnerHair, but with RSL (since it was the last film rendered using Reyes), Finding Dory was fully rendered with the RIS hair implementation in RenderMan. Monsters used the older simplified hair shader, but it was one of the first uses of importance sampling for some of Marschner’s model terms.