Thisspecial section presents new work that expands on ideas first presented at the Symposium on Interactive 3D Graphics and Games (I3D) in 2009. Significant results in interactive graphics are hard to achieve, but when produced can change the world through technology. Interactive graphics problems are intrinsically difficult. By its nature, a solution to such a problem must provide real-time guarantees and must be robust to unpredictable input. These constraints mean that it is often impossible to apply many computer science tools, such as offline and distributed computation, search or optimization methods, and user-assisted methods (even though sometimes user assistance is the point of interaction). Advances in this area therefore demand new algorithms, new data structures, and new mathematical and engineering insights.
True interactive 3D results are important because they close the loop between input and output. This closure is what enables people to create and experience virtual 3D worlds. These worlds are integral to modern game, computer assisted design, and scientific visualization applications. For games and software, the virtual world is the goal. Today's cars, films, medical equipment, and buildings are just a few examples of real-world objects that have been improved by interactive 3D practices at the design stage. Tomorrow's virtual and real worlds will benefit from work that is just now being published.
The I3D Symposium is a venue for cutting-edge computer science research in real-time graphics and human interaction. Since 1986, when the symposium was first held, the field has grown so large and sophisticated that it is now covered by several excellent conferences and journals. I3D itself expanded its size and refined its scope in response. For example, in 2005, it became an annual conference and added the phrase "and Games" to recognize the importance of the games industry in advancing interactive 3D techniques. Today, I3D is known for close integration of academia and industry, a highly-selective peer-review of papers, and an emphasis on practicality. If you're sitting in the audience at an I3D talk, you know that the technique presented truly works—frequently because you're watching a live demo.
In 2009, 87 research papers were submitted to I3D. Each was independently reviewed by at least three experts in the field, who collectively selected 28 of the submitted papers for publication and presentation at the symposium (a 32 percent acceptance rate). Based on the reviewers' comments and scoring, as chairs and editors we then invited the authors of four of those papers to incorporate new results and submit expanded versions of their work for publication in this special section of IEEE Transactions on Visualization and Computer Graphics ( TVCG). These papers received a full journal review process, with multiple iterations of editing and review.
"Two Fast Methods for High-Quality Line Visibility" by Forrester Cole and Adam Finkelstein addresses the long-standing problem of rendering stylized lines atop surfaces. Stroked lines are essential for nonphotorealistic rendering applications such as CAD and expressive animation. There are many challenges in rendering correct visibility between multiple lines: stylized lines should often overlap at a semantic level, not a pixel level; thin lines and fine style features must be filtered to limit aliasing artifacts; and for real-time rendering any solution must be efficient and map to contemporary graphics APIs such as OpenGL. The authors present two solutions, one which is straightforward to integrate into existing applications for simple lines, and another that adds a data structure capable of rendering stylization features such as overshoot and haloing.
"Parallel View-Dependent Refinement of Progressive Meshes" by Liang Hu, Pedro V. Sander, and Hugues Hoppe addresses the problem of real-time rendering of highly detailed meshes. A new algorithm for refining and coarsening a mesh at the vertex level is presented. The key innovation is a new data structure that allows limited asynchronous parallel adjustment of detail, thus enabling its implementation as a series of barrier-synchronized passes on a massively parallel processor such as a GPU. The paper shows how to implement this algorithm on current hardware with a constant space factor of overhead.
"Interactive Illumination Using Adaptive Multiresolution Splatting" by Greg Nichols and Chris Wyman presents an efficient method to render indirect global illumination. The authors focus on improving reflective shadow maps, a method that uses shadow mapping to generate virtual point lights to provide the secondary single-bounce illumination. The original formulation of reflective shadow maps involves a splatting method that is expensive due to excessive overdraw. The I3D paper presented a multiresolution method that provides a more efficient way of rendering splats. Here, the authors extend their work, providing techniques to improve quality and extending the algorithm to generate illumination from specular surfaces.
"Real-Time Creased Approximate Subdivision Surfaces" by Denis Kovacs, Jason Mitchell, Shanon Drone, and Denis Zorin extends recent work on high-quality rendering of curved surfaces with both algorithmic and implementation advances. The authors present a new method for rendering piece-wise smooth surfaces with sharp creases and corners in real time and with good quality shading near the sharp features. This is a significant result because the Catmull-Clark family of surfaces that it extends are used heavily in both entertainment and engineering modeling. This work demonstrates the practicality and close ties between industry and academia at I3D: It is a collaboration between authors at Valve Software and New York University, and the method was integrated into the commercially-available Source engine. The image from this paper on the cover of the symposium proceedings is from an in-engine short film teaser for the Team Fortress 2 video game.
These papers represent well the scope of the I3D Symposium and the quality of the ideas to be found there each year. The final versions published in this special section combine the excitement of new ideas from the symposium with the additional details, analysis, and reflection possible in the journal. We thank the authors, editors, and the TVCG EIC Thomas Ertl for ensuring both the timeliness and quality of this work, and program chairs Manuel Menezes de Oliveira Neto and Daniel G. Aliaga for organizing the 2009 symposium itself.
M. McGuire is with Williams College, Department of Computer Science, 47 Lab Campus Drive, Williamstown, MA 01267.
E. Haines is with Autodesk, Inc., 111 Eastwood Avenue, Ithaca, NY 14850. E-mail: firstname.lastname@example.org.
For information on obtaining reprints of this article, please send e-mail to: email@example.com.
received the PhD degree from Brown University in 2006. He is an assistant professor of computer science at Williams College. He is the lead author of Creating Games: Mechanics, Content, and Technology
and an editor for the Journal of Graphics, Game, and GPU Tools
, and served as cochair for the ACM Symposium on Interactive 3D Graphics and Games in 2008 and 2009 and the 2010 ACM Symposium on Non-Photorealistic Animation and Rendering in 2010. Dr. McGuire has contributed to many commercial products including the E-Ink display for the Amazon Kindle, the PeakStream high-performance computing infrastructure acquired by Google, the Titan Quest PC role-playing game, and the Marvel Ultimate Alliance 2 video game for Xbox 360. His current research spans computer vision and video games. He is using video cameras to help computers understand the 3D world around them, and is investigating new design methods for video games to increase interactivity and engagement as well as improve 3D rendering. He incorporates these research ideas into the computer graphics and game design courses that he teaches at Williams College.
received the MS degree from the Program of Computer Graphics at Cornell in 1985. He served as cochair for the ACM Symposium on Interactive 3D Graphics and Games in 2008 and 2009. He started as a researcher in the field of ray tracing, and is the creator of "sphereflake" and other benchmarking scenes. He is a coauthor of An Introduction to Ray Tracing
and has published The Ray Tracing News
for more than 20 years. He currently works in the area of interactive computer graphics, coauthoring the book Real-Time Rendering
, now in its third edition. He is an editor for the ShaderX
book series and for the Journal of Graphics, GPU, and Game Tools
, and maintainer of the Graphics Gems
code repository. He is a lead software engineer at Autodesk, Inc., working on a next-generation interactive rendering system for computer-aided design applications such as AutoCAD and Maya. He is currently implementing robust nonphotorealistic rendering techniques for various illustration styles, including pen and ink, pastels, colored pencil, and watercolor.