Institution
Alias Systems Corporation
About: Alias Systems Corporation is a based out in . It is known for research contribution in the topics: Computer graphics & Subdivision. The organization has 27 authors who have published 44 publications receiving 7325 citations. The organization is also known as: Alias|Wavefront.
Topics: Computer graphics, Subdivision, Graphics software, Rendering (computer graphics), User interface
Papers
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TL;DR: This paper proposes an unconditionally stable model which still produces complex fluid-like flows and the stability of the model allows us to take larger time steps and therefore achieve faster simulations.
Abstract: Building animation tools for fluid-like motions is an important and challenging problem with many applications in computer graphics. The use of physics-based models for fluid flow can greatly assist in creating such tools. Physical models, unlike key frame or procedural based techniques, permit an animator to almost effortlessly create interesting, swirling fluid-like behaviors. Also, the interaction of flows with objects and virtual forces is handled elegantly. Until recently, it was believed that physical fluid models were too expensive to allow real-time interaction. This was largely due to the fact that previous models used unstable schemes to solve the physical equations governing a fluid. In this paper, for the first time, we propose an unconditionally stable model which still produces complex fluid-like flows. As well, our method is very easy to implement. The stability of our model allows us to take larger time steps and therefore achieve faster simulations. We have used our model in conjuction with advecting solid textures to create many fluid-like animations interactively in twoand three-dimensions. CR Categories: I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Animation
1,640 citations
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01 Jul 2002TL;DR: This paper introduces a new quasi-conformal parameterization method, based on a least-squares approximation of the Cauchy-Riemann equations, which can parameterize large charts with complex borders, and introduces segmentation methods to decompose the model into charts with natural shapes, and a new packing algorithm to gather them in texture space.
Abstract: A Texture Atlas is an efficient color representation for 3D Paint Systems. The model to be textured is decomposed into charts homeomorphic to discs, each chart is parameterized, and the unfolded charts are packed in texture space. Existing texture atlas methods for triangulated surfaces suffer from several limitations, requiring them to generate a large number of small charts with simple borders. The discontinuities between the charts cause artifacts, and make it difficult to paint large areas with regular patterns.In this paper, our main contribution is a new quasi-conformal parameterization method, based on a least-squares approximation of the Cauchy-Riemann equations. The so-defined objective function minimizes angle deformations, and we prove the following properties: the minimum is unique, independent of a similarity in texture space, independent of the resolution of the mesh and cannot generate triangle flips. The function is numerically well behaved and can therefore be very efficiently minimized. Our approach is robust, and can parameterize large charts with complex borders.We also introduce segmentation methods to decompose the model into charts with natural shapes, and a new packing algorithm to gather them in texture space. We demonstrate our approach applied to paint both scanned and modeled data sets.
1,239 citations
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01 Aug 2001TL;DR: The method proposed here exploits physics unique to smoke in order to design a numerical method that is both fast and efficient on the relatively coarse grids traditionally used in computer graphics applications.
Abstract: In this paper, we propose a new approach to numerical smoke simulation for computer graphics applications. The method proposed here exploits physics unique to smoke in order to design a numerical method that is both fast and efficient on the relatively coarse grids traditionally used in computer graphics applications (as compared to the much finer grids used in the computational fluid dynamics literature). We use the inviscid Euler equations in our model, since they are usually more appropriate for gas modeling and less computationally intensive than the viscous Navier-Stokes equations used by others. In addition, we introduce a physically consistent vorticity confinement term to model the small scale rolling features characteristic of smoke that are absent on most coarse grid simulations. Our model also correctly handles the inter-action of smoke with moving objects.
937 citations
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24 Jul 1998TL;DR: This paper disprove the belief widespread within the computer graphics community that Catmull-Clark subdivision surfaces cannot be evaluated directly without explicitly subdividing and shows that the surface and all its derivatives can be evaluated in terms of a set of eigenbasis functions which depend only on the subdivision scheme.
Abstract: In this paper we disprove the belief widespread within the computer graphics community that Catmull-Clark subdivision surfaces cannot be evaluated directly without explicitly subdividing. We show that the surface and all its derivatives can be evaluated in terms of a set of eigenbasis functions which depend only on the subdivision scheme and we derive analytical expressions for these basis functions. In particular, on the regular part of the control mesh where Catmull-Clark surfaces are bi-cubic B-splines, the eigenbasis is equal to the power basis. Also, our technique is both easy to implement and efficient. We have used our implementation to compute high quality curvature plots of subdivision surfaces. The cost of our evaluation scheme is comparable to that of a bi-cubic spline. Therefore, our method allows many algorithms developed for parametric surfaces to be applied to Catmull-Clark subdivision surfaces. This makes subdivision surfaces an even more attractive tool for free-form surface modeling. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling—Curve, Surface, Solid, and Object Representations J.6 [Computer Applications]: Computer-Aided Engineering—Computer Aided Design (CAD)
584 citations
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24 Jul 1998TL;DR: An approach that is inspired by armatures used by sculptors, in which wire curves give definition to an object and shape its deformable features is presented, and domain curves that define the domain of deformation about an object are introduced.
Abstract: Finding effective interactive deformation techniques for complex geometric objects continues to be a challenging problem in modeling and animation. We present an approach that is inspired by armatures used by sculptors, in which wire curves give definition to an object and shape its deformable features. We also introduce domain curves that define the domain of deformation about an object. A wire together with a collection of domain curves provide a new basis for an implicit modeling primitive. Wires directly reflect object geometry, and as such they provide a coarse geometric representation of an object that can be created through sketching. Furthermore, the aggregate deformation from several wires is easy to define. We show that a single wire is an appealing direct manipulation deformation technique; we demonstrate that the combination of wires and domain curves provide a new way to outline the shape of an implicit volume in space; and we describe techniques for the aggregation of deformations resulting from multiple wires, domain curves and their interaction with each other and other deformation techniques. The power of our approach is illustrated using applications of animating figures with flexible articulations, modeling wrinkled surfaces and stitching geometry together.
396 citations
Authors
Showing all 27 results
Name | H-index | Papers | Citations |
---|---|---|---|
George Fitzmaurice | 60 | 222 | 11214 |
William Buxton | 58 | 126 | 16364 |
Gordon Kurtenbach | 48 | 88 | 7141 |
Karan Singh | 47 | 180 | 6825 |
Azam Khan | 33 | 114 | 3421 |
Eugene Fiume | 33 | 108 | 4154 |
Jos Stam | 30 | 48 | 6472 |
Bill Buxton | 28 | 72 | 5331 |
Thomas Baudel | 19 | 56 | 2954 |
Kelvin Sung | 18 | 68 | 906 |
Andrew Woo | 12 | 22 | 1486 |
Gord Kurtenbach | 9 | 10 | 598 |
Alain Chesnais | 4 | 9 | 188 |
Jerome Maillot | 4 | 5 | 1634 |
Robert J. Pieke | 3 | 3 | 310 |