Here is a collection of VFX papers, slideshows, and presentations written and released by some very smart people in our Visual Effects industry. The link at the bottom of each description will have a PDF file you can download, or read in your browser. Enjoy!
Global Illumination across Industries
Siggraph course 2010
Presented By:
Jaroslav Krivanek
This is an introduction to three other presentations that describe different types of GI renderers that are currently being used at the movie studios. Jaroslav begins by giving a great simple description of Global Illumination, and the four different types of resultant lighting effects, diffuse inter-reflections (color bleed), glossy reflections (we used to call this spec), caustics, and refractions. Then follows clear definitions of BRDF (the shading characteristics of a surface), and how this is used when calculating how much light hits every point in a scene.
“The goal of realistic rendering is to compute the amount of light reflected from visible scene surfaces that arrives to the virtual camera through image pixels. This light determines the color of image pixels”
giai2010-01-jaroslav_krivanek-notes
Image Based Lighting and Physical Shading at ILM
Presented By: Ben Snow Industrial Light and Magic
This is a great slide show by Ben Snow of a presentation he gave at Siggraph 2010, which describes how ILM lighting has changed their lighting pipeline over the years. The first version is small with only slides, the second version is much larger PDF with full text of the speech.
Here are some direct quotes:
“With visual effects for film, we’re really trying to produce filmed reality, or more correctly the view of the world that is captured on film or another medium. And it’s an important distinction.”
“In the few years leading up to Iron Man and Terminator, there had been a lot of interesting discussion and presentations at Siggraph and other conferences about physically based materials and lighting, and the move to energy conserving materials, and importance sampled ray tracing. We decided we wanted to use an energy conserving, importance sampled, image-based shading setup. The goal was a simpler, more intuitive and physically based system of lighting and rendering.”
“The system we arrived at introduced energy conservation into our shaders. This means that the amount of light that reflects or bounces off a surface can never be more than the amount of light hitting the surface.”
“The new tools also combined what we used to think of as the separate components of specular and reflection together into one component we called specular. Likewise what we used to call ambient and diffuse now are combined into diffuse.”
sigg2010_physhadcourse_ILM_slides.compressed
http://renderwonk.com/publications/s2010-shading-course/snow/sigg2010_physhadcourse_ILM.pdf
Faster Photorealism in Wonderland:
Physically based shading and lighting at Sony Pictures Imageworks
Presented By:Adam Martinez, Cg Supervisor
This presentation by Adam Martinez from SPI describes how the studio is transitioning from the traditional multi-pass rendering to a more single beauty pass, GI lighting, physically based rendering and lighting system based on the Arnold renderer. This transition makes the lookDev and lighters job more streamlined and natural because we can focus on placing, scaling, and adjusting lights and reflectors to simulate on-set studio lighting rather then rendering multiple lighting passes, and manually balancing many over-developed parameters that tried to force a relationship between direct illumination specular and reflection response.
Here are some direct quotes:
“Since we combine the specular illumination and reflection terms into a single interface, and by virtue of the Arnold renderer’s
native behavior, we also accomplished substantial interface simplification and a streamlined the user experience.”
“Rob Bredow, Imageworks’ CTO, made it clear that the push towards using Arnold, and technologies like it, was to provide more photo-realistic imagery out of the gate, but to also make our human time more productive.”