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- Thomas Lewiner, Hélio Lopes, Antônio Wilson Vieira, Geovan Tavares
- J. Graphics, GPU, & Game Tools
- 2003

Marching Cubes’ methods first offered visual access to experimental and theoretical data. The implementation of this method usually relies on a small lookup table. Many enhancements and optimizations of Marching Cubes still use it. However, this lookup table can lead to cracks and inconsistent topology. This paper introduces a full implementation of… (More)

- G A Tavares, E H Panepucci, A T Brunger
- Molecular cell
- 2001

PSD-95/SAP90 is a member of the MAGUK superfamily. In excitatory synapses, PSD-95 clusters receptors and ion channels at specific sites in the postsynaptic membrane and organizes downstream signaling and cytoskeletal molecules. We have determined the crystal structures of the apo and GMP-bound forms to 2.3 and 2.0 A resolutions, respectively, of a fragment… (More)

- Fabiano Petronetto, Afonso Paiva, Marcos Lage, Geovan Tavares, Hélio Lopes, Thomas Lewiner
- IEEE Transactions on Visualization and Computer…
- 2010

Vector fields analysis traditionally distinguishes conservative (curl-free) from mass preserving (divergence-free) components. The Helmholtz-Hodge decomposition allows separating any vector field into the sum of three uniquely defined components: curl free, divergence free and harmonic. This decomposition is usually achieved by using mesh-based methods such… (More)

- Thomas Lewiner, Hélio Lopes, Geovan Tavares
- Comput. Geom.
- 2003

Morse theory is a powerful tool in its applications to computational topology, computer graphics and geometric modeling. It was originally formulated for smooth manifolds. Recently, Robin Forman formulated a version of this theory for discrete structures such as cell complexes. It opens up several categories of interesting objects (particularly meshes) to… (More)

Morse theory has been considered a powerful tool in its applications to computational topology, computer graphics and geometric modeling. It was originally formulated for smooth manifolds. Recently, Robin Forman formulated a version of this theory for discrete structures such as cell complexes. It opens up several categories of interesting objects… (More)

- Afonso Paiva, Fabiano Petronetto, Thomas Lewiner, Geovan Tavares
- 2006 19th Brazilian Symposium on Computer…
- 2006

This paper presents a new visually realistic animation technique for objects that melt and flow. It simulates viscoplastic properties of materials such as metal, plastic, wax, polymer and lava. The technique consists in modeling the object by the transition of a non-Newtonian fluid with high viscosity to a liquid of low viscosity. During the melting, the… (More)

- Hélio Lopes, Geovan Tavares, Jarek Rossignac, Andrzej Szymczak, Alla Safonova
- Symposium on Solid Modeling and Applications
- 2002

The Edgebreaker is an efficient scheme for compressing triangulated surfaces. A surprisingly simple implementation of Edgebreaker has been proposed for surfaces homeomorphic to a sphere. It uses the Corner-Table data structure, which represents the connectivity of a triangulated surface by two tables of integers, and encodes them with less than 2 bits per… (More)

- Afonso Paiva, Fabiano Petronetto, Thomas Lewiner, Geovan Tavares
- Computer-Aided Design
- 2009

Simulations of viscoplastic materials are traditionally governed by continuum mechanics. The viscous behavior is typically modeled as an internal force, defined by diverse quantities. This work introduces a fluid model to simulate the viscoplastic effect of solid materials, such as plastic, wax, clay and polymer. Our method consists in modeling a solid… (More)

- Thales Vieira, Alex Laier Bordignon, +4 authors Thomas Lewiner
- Comput. Graph. Forum
- 2009

The definition of a good view of a 3D scene is highly subjective and strongly depends on both the scene content and the 3D application. Usually, camera placement is performed directly by the user, and that task may be laborious. Existing automatic virtual cameras guide the user by optimizing a single rule, e.g. maximizing the visible silhouette or the… (More)

Morse theory is a fundamental tool for investigating the topology of smooth manifolds. This tool has been extended to discrete structures by Forman, which allows combinatorial analysis and direct computation. This theory relies on discrete gradient vector fields, whose critical elements describe the topology of the structure. The purpose of this work is to… (More)