Computer Graphics World

April 2011

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By YONI KOENIG Rendering Creative Freedom: Refining Workflow for 3D CGI require inordinate amounts of labor—tightly controlled scripting of all actors and objects on the set and camera locations, angles and lighting predetermined long before the cameras roll, and more. This particular scenario may sound far-fetched, but 3D animators and I artists face similar workflow challenges when setting up and adjusting lighting, materials, shadows, and angles to achieve the desired end result. However, realistically determining the creative look and production qual- ity of an animated shot is a time-consuming process that requires render- ing layers and assembling everything in a compositing application. The initial setup of a scene doesn’t require this type of sequential workflow. However, small modifications to a scene, such as adding sheen to a character’s hair, requires the artists to go back and re-render the entire sequence before they can actually see how it looks. In fact, almost any change to visual appearance, no matter how subtle, can become very time-consuming and costly from a creative standpoint: It requires adjusting, rendering, reviewing, and repeating serial dis- crete steps. This type of iterative sequential workflow is the norm for 3D CG animation and is similar to the workflow challenges video editors faced 20 years ago, before real-time non-linear editing programs be- came widely available. Back in the day when tape-to-tape editing was in practice, each piece of video had to be laid down to the recorder in a linear sequence. Once the process was under way, making a simple change was not possible without completely re-editing the footage that followed the change. However, once non-linear editing tools entered the mainstream, video workflow forever changed. Instead of building a program sequence one shot at a time, non-linear systems allowed film and video makers to work with any piece of footage and see the results as they unfolded. This simple modification to editing allows editors Yoni Koenig is chief scientist at StudioGPU, creators of MachStudio Pro. He has been involved in the creation of 3D animation for more than 20 years and continues to explore better ways to utilize the power of the GPU to improve and streamline creative 3D workflow. 8 April 2011 For more creative results, CGI artists need a non-sequential workflow, where they can see results as they happen and act accordingly. Non-linear Workflow Faster processors and professional graphics accelerators are advancing technology at an astounding rate, resulting in more powerful CPUs and GPUs for faster final rendering using commercial rendering and ray- tracing programs. Many accelerated rendering solutions, such as Chaos Group’s V-Ray, Caustic Graphics’ CausticRT, Mental Images’ Mental Ray, and others, continue to raise the bar for realistic visualization. And the promise of even faster final rendering using the new line of graphics accelerator boards, like Evergreen from AMD and Fermi from Nvidia, will continue to drive innovation beyond the imagination. Faster final rendering is only one part of the equation, however. The real breakthrough comes with acceleration of the entire workflow, allowing artists to work in a non-linear environment to make and view changes as fast as the artist (or client) can envision them. Imagine being able to add a light to a scene on the fly, make adjust- ments, and see the shadows, glows, blooms, AO, reflections, and so on, almost exactly as they will appear in a final render. No need to look at the interface and type in a number. Instead, move a slider and watch the im- age change directly. Scrub the timeline and as the camera moves, dynami- cally manipulate lighting, depth of field, motion blur, materials, or turn compositing layers on or off without having to re-render the scene. Jump to an arbitrary time point in a scene, make a change, and see the results without having to click a render button or even wait for a progressive scan magine a world where the filmmaker shoots a scene blindfolded without the ability to see who or what is actually being captured on film until the footage is in review. A workflow that limiting would greater flexibility and control over the final footage, along with a hefty time-savings in production.

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