Have we reached the end of the road for conventional 3D rendering?
Siggraph 2009 ended Friday, and I've spent the last few days digesting what I learned there. Although I've been involved in the graphics industry since 1990 and I've attended Siggraph most years since 1992, a crisis of sorts seems to have snuck up on me.
At the High Performance Graphics conference before the main show, keynote speeches from Larry Gritz of Sony Pictures Imageworks and Tim Sweeney of Epic Games showed that traditional 3D-rendering methods are being augmented and even supplanted by new techniques for motion-picture production as well as real-time computer games.
Gritz reckoned that 3D became a fully integrated element of the moviemaking process in 1989 when computer-generated characters first interacted with human characters in James Cameron's "The Abyss."
Gritz described how Imageworks has moved to a new ray-tracing rendering system called "Arnold" for several films currently in production, replacing the Reyes (Render Everything Your Eyes See) rendering system, probably the most widely used technology in the industry.
According to Gritz, Reyes rendering led to unmanageable complexity in the artistic component of the production process, outweighing the render-time advantages of the Reyes method. But Gritz says even these advantages diminished as the demand for higher quality drove Imageworks to make more use of ray tracing and a sophisticated lighting model called global illumination.
The bottom line for Imageworks is that Arnold, which was licensed from Marcos Fajardo of Solid Angle, takes longer to do the final rendering, but is easier on the artists and makes it easier to create the models and lighting effects--a net win.
Sweeney echoed this theme the next day, which surprised me considering Sweeney's focus is real-time rendering for 3D games--notably with Epic's Unreal Engine, which has been used in hundreds of 3D games on all the major platforms. Game rendering uses far less sophisticated techniques because each frame has to be rendered in perhaps one-sixtieth of a second, not the four or five hours on average that can be devoted to a single frame of a motion picture.
It seems that Sweeney is also ... Read more
Dean Takahashi sent me an e-mail pointing to a piece he wrote on VentureBeat describing statements Wednesday by Intel's Chief Technical Officer Justin Rattner targeted at NVIDIA. CNET's own Brooke Crothers covered the same story and provides additional background here.
Intel Chief Technology Officer Justin R. Rattner
(Credit: Intel)The technology at issue relates to 3D graphics for PCs. All current PC graphics chips use what's called polygon-order rendering. All of the polygons that make up the objects to be displayed are processed one at a time. The graphics chip figures out where each polygon should appear on the screen and how much of it will be visible or obstructed by other polygons.
Ray tracing achieves similar results by working through each pixel on the screen, firing off a "ray" (like a backward ray of light) that bounces off the polygons until it reaches a light source in the scene. Ray tracing produces natural lighting effects but takes a lot more work.
(That's the short version, anyway. For more details, you could dig up a copy of my 1997 book Beyond Conventional 3D. Alas, the book is long since out of print.)
Ray tracing is easily implemented in software on a general-purpose CPU, and indeed, most of the computer graphics you see in movies and TV commercials are generated this way, using rooms full of PCs or blade-server systems.
Naturally, Intel loves ray tracing, and there are people at Intel working to ... Read more
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