https://www.npcglib.orgNon-photorealistic computer graphics resources.en-usCopyright 2010, NPCGLibstathis@npcglib.orgWed, 5 May 2010 10:06:39 +0100http://blogs.law.harvard.edu/tech/rss600 https://www.npcglib.org/paper.php?entryid=840 https://www.npcglib.org/paper.php?entryid=840 <pre>@inbook{Rost:2009:OSL, author = {Randi J. Rost and Bill Licea-Kane}, editor = {}, title = {OpenGL Shading Language}, doi = {}, abstract = {A significant amount of computer graphics research has been aimed at achieving more and more realistic renditions of synthetic scenes. A longtime goal has been to render a scene so perfectly that it is indistinguishable from a photograph of the real scene, a goal called PHOTOREALISM. With the latest graphics hardware, some photorealistic effects are becoming possible in real-time rendering. This quest for realism is also reflected in graphics APIs such as OpenGL. The OpenGL specification defines specific formulas for calculating effects such as illumination from light sources, material properties, and fog. These formulas attempt to define effects as realistically as possible while remaining relatively easy to implement in hardware, and they have duly been cast into silicon by intrepid graphics hardware designers. But the collection of human art and literature shows us that photorealism is not the only important style for creating images. The availability of lowcost programmable graphics hardware has sparked the growth of an area called NON-PHOTOREALISTIC RENDERING, or NPR. Researchers and practitioners in this field are attempting to use computer graphics to produce a wide range of artistic effects other than photorealism. In this chapter, we look at a few examples of shaders whose main focus is something other than generating results that are as realistic as possible.}, chapter = {Chapter 18 - Non-photorealistic Shaders}, pages = {507--532}, publisher = {Addison-Wesley}, year = {2009}, volume = {}, series = {}, address = {}, edition = {3rd}, month = {}, note = {} }</pre> Randi J. Rost, Bill Licea-Kane Wed, 05 May 2010 10:06:29 +0100 https://www.npcglib.org/paper.php?entryid=839 https://www.npcglib.org/paper.php?entryid=839 <pre>@article{Paiva:2009:FHF, author = {Afonso Paiva and Emilio Vital Brazil and Fabiano Petronetto and Mario Costa Sousa}, title = {Fluid-based hatching for tone mapping in line illustrations}, doi = {10.1007/s00371-009-0322-8}, abstract = {This paper presents a novel meshless, physically-based framework for line art rendering of surfaces with complex geometry and arbitrary topology. We apply an inviscid ?uid ?ow simulation using Smoothed Particles Hydrodynamics to compute the global velocity and cross ?elds over the surface model. These ?elds guide the automatic placement of strokes while extracting the geometric and topological coherence of the model. Target tones are matched by tonal value maps allowing different hatching and crosshatching effects. We demonstrate the simplicity and effectiveness of our method with sample renderings obtained for a variety of models.}, journal = {The Visual Computer}, year = {2009}, volume = {25}, number = {5-7}, pages = {519--527}, month = {May}, note = {} }</pre> Afonso Paiva, Emilio Vital Brazil, Fabiano Petronetto, Mario Costa Sousa Wed, 10 Mar 2010 09:54:15 +0100 https://www.npcglib.org/paper.php?entryid=838 https://www.npcglib.org/paper.php?entryid=838 <pre>@inproceedings{Judd:2007:ARF, author = {Tilke Judd and Frédo Durand and Edward Adelson}, title = {Apparent ridges for line drawing}, doi = {http://doi.acm.org/10.1145/1275808.1276401}, abstract = {Three-dimensional shape can be drawn using a variety of feature lines, but none of the current definitions alone seem to capture all visually-relevant lines. We introduce a new definition of feature lines based on two perceptual observations. First, human perception is sensitive to the variation of shading, and since shape perception is little affected by lighting and reflectance modification, we should focus on normal variation. Second, view-dependent lines better convey smooth surfaces. From this we define view-dependent curvature as the variation of the surface normal with respect to a viewing screen plane, and apparent ridges as the loci of points that maximize a view-dependent curvature. We present a formal definition of apparent ridges and an algorithm to render line drawings of 3D meshes. We show that our apparent ridges encompass or enhance aspects of several other feature lines.}, booktitle = {SIGGRAPH '07: ACM SIGGRAPH 2007 papers}, year = {2007}, editor = {}, volume = {}, number = {}, series = {}, pages = {19}, address = {}, month = {}, organization = {}, publisher = {ACM}, note = {} }</pre> Tilke Judd, Frédo Durand, Edward Adelson Mon, 01 Mar 2010 21:08:08 +0100 https://www.npcglib.org/paper.php?entryid=828 https://www.npcglib.org/paper.php?entryid=828 <pre>@article{Park:2008:PAU, author = {Young Sup Park and Kyung Hyun Yoon}, title = {Painterly animation using motion maps}, doi = {http://dx.doi.org/10.1016/j.gmod.2007.06.001}, abstract = {Starting from an input video, we replicate the manual technique of paint-on-glass animation. Motion maps are used to represent the regions where changes occur between frames. Edges are the key to identifying frame-to-frame changes, and a strong motion map is constructed from the edges in each frame, displaced by the motion vector. A second, weak motion map records the other pixels where there is significant movement between frames. These maps are used to generate the brush strokes necessary to convert one 'painted' frame into the next. Local gradient interpolation, based robustly on the edges, is used to determine the orientation of the brush strokes, and we avoid holes in the image by making additional strokes with smaller brushes. We also employ MSE data in evaluating temporal coherence between frames. }, journal = {Graphical Models}, year = {2008}, volume = {70}, number = {1-2}, pages = {1--15}, month = {January-March}, note = {} }</pre> Young Sup Park, Kyung Hyun Yoon Fri, 26 Feb 2010 12:17:27 +0100 https://www.npcglib.org/paper.php?entryid=836 https://www.npcglib.org/paper.php?entryid=836 <pre>@article{Kawamoto:2009:ELT, author = {Shin-ichi Kawamoto and Tatsuo Yotsukura and Ken Anjyo and Satoshi Nakamura}, title = {Efficient lip-synch tool for 3D cartoon animation}, doi = {10.1002/cav.250}, abstract = {We propose a set of algorithms to efficiently make speech animation for 3D cartoon characters. Our prototype system is based on blendshapes, a linear interpolation technique, which is widely used in facial animation practice. In our system, a few base target shapes of the character, prerecorded voice, and its transcription are required as input. We describe a simple technique that amplifies the target shapes from few inputs using a generic database of viseme mouth shapes. We also introduce additional lip-synch editing parameters that allow designers to quickly tune the lip movements. Based on these, we implement our prototype system as a Maya plug-in. The demonstration movies created with this system illustrate well the practicality of our approach.}, journal = {Computer Animation and Virtual Worlds}, year = {2009}, volume = {19}, number = {3-4}, pages = {247--257}, month = {}, note = {Special Issue: CASA'2008 Special Issue} }</pre> Shin-ichi Kawamoto, Tatsuo Yotsukura, Ken Anjyo, Satoshi Nakamura Wed, 24 Feb 2010 19:48:21 +0100 https://www.npcglib.org/paper.php?entryid=837 https://www.npcglib.org/paper.php?entryid=837 <pre>@article{Zhuang:2009:PCC, author = {Yueting Zhuang and Jun Yu and Jun Xiao and Cheng Chen}, title = {Perspective-aware cartoon clips synthesis}, doi = {http://dx.doi.org/10.1002/cav.258}, abstract = {In this paper we propose an approach, which allows the users to synthesize cartoon clips according to the perspective of the background image. In order to construct the cartoons smoothly, the character's edge distance and motion direction distance are demonstrated to be the factors affecting the human perception in similarity evaluation, and utilized in cartoon clips synthesis. When applying the generated cartoons to the background image, in which the perspective exists, the size of the character is coordinated according to the scaling factor calculated from the vanishing line. The experiment results demonstrate that our approach can synthesize the cartoon clips more smoothly compared with other single frame reusing strategies. The generated cartoons, which are applied to the background image, can be accepted by the human perception well.}, journal = {Computer Animation and Virtual Worlds}, year = {2009}, volume = {19}, number = {3-4}, pages = {355--364}, month = {}, note = {Special Issue: CASA'2008 Special Issue} }</pre> Yueting Zhuang, Jun Yu, Jun Xiao, Cheng Chen Wed, 24 Feb 2010 19:47:13 +0100 https://www.npcglib.org/paper.php?entryid=835 https://www.npcglib.org/paper.php?entryid=835 <pre>@article{Baxter:2009:NMF, author = {William Baxter and Pascal Barla and Ken Anjyo}, title = {N-way morphing for 2D animation}, doi = {http://dx.doi.org/10.1002/cav.306}, abstract = {We present a novel approach to the creation of varied animations from a small set of simple 2D input shapes. Instead of providing a new 2D shape for each keyframe of an animation sequence, we interpolate between a few example shapes in a reduced pose-space. Similar approaches have been presented in the past, but were restricted in the types of input or range of deformations allowed. In order to address these limitations, we reformulate the problem as an N-way morphing process on 2D input bitmap or vector graphics. Our formulation includes an N-way mapping technique, an efficient, rigidity preserving nonlinear blending function, improved extrapolation and a novel scattered data interpolation technique to manage the reduced pose-space. The resulting animations are correlated to paths in the reduced pose-space, allowing users to intuitively and interactively control temporal behaviours with simple gestures. We demonstrate our techniques in several example animations.}, journal = {Computer Animation and Virtual Worlds}, year = {2009}, volume = {20}, number = {2-3}, pages = {79--87}, month = {}, note = {} }</pre> William Baxter, Pascal Barla, Ken Anjyo Wed, 24 Feb 2010 19:30:59 +0100 https://www.npcglib.org/paper.php?entryid=834 https://www.npcglib.org/paper.php?entryid=834 <pre>@article{Sugisaki:2009:ISF, author = {Eiji Sugisaki and Hock Soon Seah and Feng Tian and Shigeo Morishima}, title = {Interactive shadowing for 2D Anime}, doi = {http://dx.doi.org/10.1002/cav.306}, abstract = {In this paper, we propose an instant shadow generation technique for 2D animation, especially Japanese Anime. In traditional 2D Anime production, the entire animation including shadows is drawn by hand so that it takes long time to complete. Shadows play an important role in the creation of symbolic visual effects. However shadows are not always drawn due to time constraints and lack of animators especially when the production schedule is tight. To solve this problem, we develop an easy shadowing approach that enables animators to easily create a layer of shadow and its animation based on the character's shapes. Our approach is both instant and intuitive. The only inputs required are character or object shapes in input animation sequence with alpha value generally used in the Anime production pipeline. First, shadows are automatically rendered on a virtual plane by using a Shadow Map1 based on these inputs. Then the rendered shadows can be edited by simple operations and simplified by the Gaussian Filter. Several special effects such as blurring can be applied to the rendered shadow at the same time. Compared to existing approaches, ours is more efficient and effective to handle automatic shadowing in real-time. }, journal = {Computer Animation and Virtual Worlds}, year = {2009}, volume = {20}, number = {2-3}, pages = {395--404}, month = {}, note = {Special Issue: CASA' 2009 Special Issue} }</pre> Eiji Sugisaki, Hock Soon Seah, Feng Tian, Shigeo Morishima Wed, 24 Feb 2010 19:24:37 +0100 https://www.npcglib.org/paper.php?entryid=833 https://www.npcglib.org/paper.php?entryid=833 <pre>@inproceedings{Choudhury:2009:RTN, author = {A.N.M. Imroz Choudhury and Steven G. Parker}, title = {Ray Tracing NPR-Style Feature Lines}, doi = {http://doi.acm.org/10.1145/1572614.1572616}, abstract = {We present an algorithm for rendering high-quality line primitives of controllable on-screen width within a ray tracing framework, which can render simple NPR-style feature lines, including silhouette edges, crease lines, and primitive intersection lines. The algorithm is based on a variant of cone tracing, which measures distances in screen space and is used to detect and render feature lines. This technique opens ray tracing up to previously difficult or impossible styles of rendering, such as mesh visualization, as well as a variety of NPR techniques, such as apparent ridges.}, booktitle = {NPAR '09: Proceedings of the 7th International Symposium on Non-Photorealistic Animation and Rendering}, year = {2009}, editor = {}, volume = {}, number = {}, series = {}, pages = {5--14}, address = {}, month = {}, organization = {}, publisher = {ACM}, note = {} }</pre> A.N.M. Imroz Choudhury, Steven G. Parker Tue, 23 Feb 2010 16:47:36 +0100 https://www.npcglib.org/paper.php?entryid=829 https://www.npcglib.org/paper.php?entryid=829 <pre>@article{Cole:2008:WDP, author = {Forrester Cole and Aleksey Golovinskiy and Alex Limpaecher and Heather Stoddart Barros and Adam Finkelstein and Thomas A. Funkhouser and Szymon Rusinkiewicz}, title = {Where Do People Draw Lines?}, doi = {10.1145/1360612.1360687}, abstract = {This paper presents the results of a study in which artists made line drawings intended to convey specific 3D shapes. The study was designed so that drawings could be registered with rendered images of 3D models, supporting an analysis of how well the locations of the artists' lines correlate with other artists', with current computer graphics line definitions, and with the underlying differential properties of the 3D surface. Lines drawn by artists in this study largely overlapped one another (75% are within 1mm of another line), particularly along the occluding contours of the object. Most lines that do not overlap contours overlap large gradients of the image intensity, and correlate strongly with predictions made by recent line drawing algorithms in computer graphics. 14% were not well described by any of the local properties considered in this study. The result of our work is a publicly available data set of aligned drawings, an analysis of where lines appear in that data set based on local properties of 3D models, and algorithms to predict where artists will draw lines for new scenes.}, journal = {ACM Transactions on Graphics (Proceedings of SIGGRAPH 2008)}, year = {2008}, volume = {27}, number = {3}, pages = {88:1--11}, month = {August}, note = {} }</pre> Forrester Cole, Aleksey Golovinskiy, Alex Limpaecher, Heather Stoddart Barros, Adam Finkelstein, Thomas A. Funkhouser, Szymon Rusinkiewicz Tue, 15 Dec 2009 15:59:21 +0100