{"title":"Non-photorealistic rendering using watercolor inspired textures and illumination","authors":"E. Lum, K. Ma","doi":"10.1109/PCCGA.2001.962888","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962888","url":null,"abstract":"The authors present a watercolor inspired method for the rendering of surfaces. Our approach mimics the watercolor process by building up an illuminated scene through the compositing of several layers of semitransparent paint. The key steps consist of creating textures for each layer using LIC (Line Integral Convolution) of Perlin Noise (K. Perlin, 1985), and then calculating the layer thickness distribution using an inverted subtractive lighting model. The resulting watercolor-style images have color coherence that results from the mixing of a limited palette of paints. The new lighting model helps to better convey large shape changes, while texture orientations give hints of less dominant features. The rendered images therefore possess perceptual clues to more effectively communicate shape and texture information.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129585713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Biermann, Ioana M. Boier-Martin, D. Zorin, F. Bernardini
{"title":"Sharp features on multiresolution subdivision surfaces","authors":"H. Biermann, Ioana M. Boier-Martin, D. Zorin, F. Bernardini","doi":"10.1109/PCCGA.2001.962867","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962867","url":null,"abstract":"In this paper we describe a method for creating sharp features and trim regions on multiresolution subdivision surfaces along a set of user-defined curves. Operations such as engraving, embossing, and trimming are important in many surface modeling applications. Their implementation, however, is non-trivial due to computational, topological, and smoothness constraints that the underlying surface has to satisfy. The novelty of our work lies in the ability to create sharp features anywhere on a surface and in the fact that the resulting representation remains within the multiresolution subdivision framework. Preserving the original representation has the advantage that other operations applicable to multiresolution subdivision surfaces can subsequently be applied to the edited model. We also introduce an extended set of subdivision rules for Catmull-Clark surfaces that allows the creation of creases along diagonals of control mesh faces.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116824665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Myung-Soo Kim, Joon-Kyung Seong, Dae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin Choi
{"title":"A physical 3D trackball","authors":"Myung-Soo Kim, Joon-Kyung Seong, Dae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin Choi","doi":"10.1109/PCCGA.2001.962866","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962866","url":null,"abstract":"We present a simple method for constructing a physical 3D trackball that can input 3D rotation about an arbitrary axis. This input device is based on multiple sensors that can detect the tangential velocities at certain points on the boundary sphere of the trackball. A mathematical analysis is given for the optimal locations of multiple sensors. A prototype hardware device has been built for the 3D trackball. We demonstrate the effectiveness of this input device in 3D rotation by comparing its performance with the Magellan/SPACE MOUSE.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127504741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adaptive smoothing tangential direction fields on polygonal surfaces","authors":"Y. Ohtake, Masahiro Horikawa, A. Belyaev","doi":"10.1109/PCCGA.2001.962872","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962872","url":null,"abstract":"The paper develops a simple and effective method for adaptive smoothing tangential direction fields defined on piecewise smooth surfaces approximated by triangle meshes. The method consists of simultaneous and iterative updating each vertex direction by a weighted sum of the directions at the neighboring vertices. The weights themselves depend on directions: if the direction at a given vertex differs strongly from the direction at a neighboring vertex, then the weight associated with that neighboring direction is chosen small. Choosing such nonlinear weights allows us to preserve important direction field discontinuities during the smoothing process. Applications of the developed smoothing technique to curvature extrema detection and non-photorealistic rendering with curvature lines are given.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124658513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Integrating physics-based modeling with PDE solids for geometric design","authors":"Haixia Du, Hong Qin","doi":"10.1109/PCCGA.2001.962873","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962873","url":null,"abstract":"PDE techniques, which use partial differential equations (PDEs) to model the shapes of various real-world objects, can unify their geometric attributes and functional constraints in geometric computing and graphics. This paper presents a unified dynamic approach that allows modelers to define the solid geometry of sculptured objects using the second-order or fourth-order elliptic PDEs subject to flexible boundary conditions. Founded upon the previous work on PDE solids by Bloor and Wilson (1989, 1990, 1993), as well as our recent research on the interactive sculpting of physics-based PDE surfaces, our new formulation and its associated dynamic principle permit designers to directly deform PDE solids whose behaviors are natural and intuitive subject to imposed constraints. Users can easily model and interact with solids of complicated geometry and/or arbitrary topology from locally-defined PDE primitives through trimming operations. We employ the finite-difference discretization and the multi-grid subdivision to solve the PDEs numerically. Our PDE-based modeling software offers users various sculpting toolkits for solid design, allowing them to interactively modify the physical and geometric properties of arbitrary points, curve spans, regions of interest (either in the isoparametric or nonisoparametric form) on boundary surfaces, as well as any interior parts of modeled objects.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121519051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modeling realistic virtual hairstyles","authors":"Yizhou Yu","doi":"10.1109/PCCGA.2001.962885","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962885","url":null,"abstract":"The author presents an effective method for modeling realistic curly hairstyles, taking into account both artificial hairstyling processes and natural curliness. The result is a detailed geometric model of hairs that can be rendered and animated via existing methods. Our technique exploits the analogy between hairs and a vector field; it interactively and efficiently models global and local hair flows by superimposing procedurally defined vector field primitives that have local influence. Usually only a very small number of vector field primitives are needed to model a complicated hairstyle. An initial model of hair strands is extracted from the superimposed vector fields by tracing their field lines. Random natural or artificial curliness can be added to the initial model through a parametric hair offset function with a randomized distribution of parameters over the scalp. Techniques for shearing and clustering are also designed to improve the overall appearance of the hair model. Our technique has been successfully applied to generate a variety of realistic hairstyles with different curliness and length distributions.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133493157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Direct reconstruction of displaced subdivision surface from unorganized points","authors":"W. Jeong, Chang-Hun Kim","doi":"10.1109/PCCGA.2001.962869","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962869","url":null,"abstract":"We propose a new mesh reconstruction algorithm that produces a displaced subdivision mesh directly from unorganized points. The displaced subdivision surface is a new mesh representation that defines a detailed mesh with a displacement map over a smooth domain surface. This mesh representation has several benefits-compact mesh size, piecewise regular connectivity-to overcome limitations of an irregular mesh produced by an ordinary mesh reconstruction scheme, but the original displaced subdivision surface generation algorithm needs an explicit polygonal mesh to be converted. Our approach is producing displaced subdivision surface directly from input points during the mesh reconstruction process. The main ideas of our algorithm are building initial coarse control mesh by the shrink-wrapping like projection and sampling fine surface detail from unorganized points along the each limit vertex normal without any connectivity information of given points. We employ an existing subdivision surface fitting scheme to generate a parametric domain surface, and suggest a surface detail sampling scheme that determines a valid sampling triangle which can be made with combinations of input points. We show several reconstruction examples and applications to show the validity of suggested sampling technique and benefits of the result like multiresolution modeling.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131947255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stream bubbles for steady flow visualization","authors":"Bing Zhang, A. Pang","doi":"10.1109/PCCGA.2001.962870","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962870","url":null,"abstract":"This paper introduces a new relatively inexpensive technique - stream bubbles for 3D flow visualization. The physical analogy to this technique are bubbles that can be observed in nature with different shapes and varying speeds. A stream bubble is a surface, defined by a small set of vertices, advected through a flow field. It can easily manifest flow features like twist, stretch, expansion and rotation. Upon encountering an obstacle, stream bubbles will automatically erode and/or split in an intuitively geometric way. For highly divergent and vortical fields, it can also break apart based on the aspect ratio of the bounding volume. When two or more stream bubbles meet, no explicit merge operation is needed since the surfaces will simply intersect each other to form a composite surface. No effort is made to make the intersection smooth. Stream bubbles may be of different sizes. Larger bubbles give a coarse global view of the flow structure, while smaller ones give a more accurate depiction. In addition, our interface provides an interactive, multi-resolution visualization environment facilitated with an animated or step-by-step playback function.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122732863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dual mesh resampling","authors":"G. Taubin","doi":"10.1109/PCCGA.2001.962871","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962871","url":null,"abstract":"The dual of a 2-manifold polygonal mesh without boundary is commonly defined as another mesh with the same topology (genus) but different connectivity (vertex-face incidence), in which faces and vertices occupy complementary locations and the position of each dual vertex is computed as the center of mass (barycenter or centroid) of the vertices that support the corresponding face. This barycenter dual mesh operator is connectivity idempotent but not geometrically idempotent for any choice of vertex positions, other than constants. In this paper we construct a new resampling dual mesh operator that is geometrically idempotent for the largest possible linear subspace of vertex positions. We look at the primal and dual mesh connectivities as irregular sampling spaces, and at the rules to determine dual vertex positions as the result of a resampling process that minimizes signal loss. Our formulation, motivated by the duality of Platonic solids, requires the solution of a simple least-squares problem. We introduce a simple and efficient iterative algorithm closely related to Laplacian smoothing, and with the same computational cost. We also characterize the configurations of vertex positions where signal loss does and does not occur during dual mesh resampling, and the asymptotic behavior of iterative dual mesh resampling in the general case. Finally, we describe the close relation existing with discrete fairing and variational subdivision, and define a new primal-dual interpolatory recursive subdivision scheme.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127082983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"3D geometry compression recent advances and challenges","authors":"G. Taubin","doi":"10.1109/PCCGA.2001.962851","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962851","url":null,"abstract":"Polyhedral models, which are used in most graphics applications, require considerable amounts of storage, even when they only approximate precise shapes with limited accuracy. To support internet access to 30 models of complex virtual environments or assemblies for electronic shopping, collaborative CAD, multi-player video games, scientific visualization, representations of 30 shapes must be compressed by several orders of magnitude. In this talk I will describe the state of the art in schemes for lossy and loss-less compression of triangle and polygonal meshes, including progressive approaches. In additions to single-resolution compression schemes for triangle and polygonal meshes, which result in compressed formats of less than a byte per triangle, multiresolution progressive rejinement approaches have advanced to the point of challenging the best single resolution schemes in compression eficiency. Along with surface simplijication or decimation methods, these approaches, which change the surj5ace topology while approximating the geometry, can be regarded as lossy compression schemes. Finaly, I will describe the status of standardization efforts and open problems.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129756202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}