News Release

Henrik Wann Jensen, Assistant Professor, Computer Science a nd Engineering

San Diego, CA, January 21, 2004 - - A computer science professor from the University of California, San Diego (UCS D) who has helped pave the way for photo-realistic, computer-generated humans in the movies will be honored by the Academy of Motion Picture Arts and Sciences. Henrik Wann Jensen will receive a Technical Achievement Award from the Academy a t a ceremony at the Ritz Carlton Huntington Hotel in Pasadena, CA, on February 1 4.

The Jacobs School of Engineering assistant professor and two former colleague s -- Stanford University professor Pat Hanrahan and Cornell University assistant professor Stephen Marschner -- will be recognized for "their pioneering researc h in simulating subsurface scattering of light in translucent materials." The Ac ademy, which rarely honors academics outside the movie industry, cited the profe ssors' joint 2001 paper that laid out a "Practical Model for Subsurface Light Tr ansport." That paper, on which Jensen was the principal author, provided a model for rendering the effect of light on translucent surfaces, such as skin or marb le.

Even before the paper was published in 2001, Jensen was invited to speak at m ajor visual-effects companies such as Industrial Light & Magic (ILM) and Pix ar, which subsequently incorporated the technology into their visual-effects sof tware. "It has been heartening to see how quickly Hollywood adopted this technol ogy," said Jensen. "Almost all big-budget films with extensive visual effects no w incorporate at least some elements of our model, and the industry is on its wa y to being able to create computer-animated human characters that truly look rea l."

Jensen has grappled with ways to replicate the appearance of natural phenomen a and materials since the mid 1990s, when he developed a method called 'photon m apping' to replicate the look of light on a scene from one or more sources. That process is widely used in the computer-graphics industry, but the researcher re cognized that it fell short when rendering translucent materials such as milk, m arble, and snow -- or skin, eyes and teeth.

Previous visual-effects technology assumed that light on any surface reflects from the same point where it hits, as it does on a metal surface. The result: i mages that appear hard -- like rock or plastic. "That is why the early successes in digital animation, such as Jurassic Park and Toy Story, featured primarily n on-human characters," explained the Danish academic, who is co-director of a new Graphics and Vision group within UCSD's Computer Science and Engineering depart ment.

Drawing insight from a medical text, Jensen realized that existing effects di d not take into account a phenomenon known as 'subsurface scattering.' On transl ucent materials, light penetrates the surface and scatters, and the photons then reflect out from various points away from where they entered, at varying angles . "This scattering effect below the surface was understood as a medical phenomen on, but wasn't incorporated into computer graphics until our model, which mathem atically accounts for the way those photons scatter," said Jensen.

According to the Academy citation, "This mathematical model contributed subst antially to the development and implementation of practical techniques for simul ating subsurface scattering of light in translucent materials for computer-gener ated images in motion pictures."

Indeed, the Academy is bestowing a separate Technical Achievement Award to th e visual-effects artists responsible for first implementing Jensen's model in th e movie industry. ILM's Christophe Hery (Harry Potter and the Chamber of Secrets and Terminator 3), as well as Ken McGaugh and Joe Letteri (who supervised visua l-effects on the second and third installments of the Lord of the Rings trilogy) were cited for developing those techniques to "create realistic-looking skin on digitally created characters," noted the Academy. "The character of Gollum in t he Lord of the Rings trilogy and Dobby in Harry Potter will remain landmarks, be cause for the first time they gave movie-goers the sense that they were watching flesh-and-bone characters," said Jensen. "We are entering an era when skin can be rendered true to life, allowing audiences to forget that the character is syn thetic rather than real. This is a disruptive technology that is changing the wa y people talk about perception of simulation."

Jensen also believes it is only a matter of time before the verisimilitude of characters such as Gollum and Dobby makes its way into videogames. "The accurat e rendering of light under a translucent surface using our model requires much m ore computing power than is currently available," said Jensen. "But that will ch ange as new game consoles such as PlayStation 3 reach the market and allow game designers to create characters and objects that absorb and reflect light just as they do in reality." (Sony's PlayStation 3 and other next-generation consoles a re expected to be released starting in 2006.)

Note to Editors:
High-res photos rendered using Prof. Jensen's techniques can be downloaded here.
Mpeg, Quicktime and .avi animations can be downloaded here.