Paulo Roma Cavalcanti

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We present a formulation for achieving “as rigid as possible” deformations of 3D models using a Moving Least Squares (MLS) approach. This research was inspired by the work of Schaefer et al.[25] which describes an approach solving a 2D version of the same problem. Our main contribution is showing how the problem may be efficiently handled in 3D for both(More)
This paper deals with the problem of creating and maintaining a spatial subdivision, deened by a set of surface patches. The main goal is to create a set of functions which provides a layer of abstraction capable of hiding the geometric and topological problems which occur when one creates and manipulates spatial subdivisions. The study of arbitrary spatial(More)
In this paper we summarize our experiences with 3D constrained Delaunay triangulation algorithms for industrial applications. In addition, we report a robust implementation process for constructing 3D constrained triangulations from initial unconstrained triangulations, based on a minimalist approach, in which we minimize the use of geometrical operations(More)
We address the problem of an efficient image-space reconstruction of adaptively sampled scenes in the context of point-based and linebased graphics. The image-space reconstruction offers an advantageous time complexity compared to surface splatting techniques and, in fact, our improved GPU implementation performs significantly better than splatting(More)
Earth scientists acquire and interpret a variety of data in an attempt to define the best description of subsurface geological structures, or an earth model, as the data permit. The generation of numerical meshes derived from an earth model is a necessary critical step to provide specific data representations such as finite difference grids or finite(More)
Image-space reconstruction of continuous surfaces from scattered one-pixel projections of points is known to potentially offer an advantageous time complexity compared to surface splatting techniques. We propose a new algorithm for hardware-accelerated image-space reconstruction using pull-push interpolation and present an efficient GPU implementation.(More)
We present a generic programming approach to the implementation of multiresolution spatial decompositions. From a set of simple and necessary requirements, we arrive at the Binary Multitriangulation (BMT) concept. We also describe a data structure that models the BMT concept in its full generality. Finally, we discuss applications of the BMT to(More)
A strategy is presented to define background meshes based on crystal lattices. Crystal-based background meshes have much better initial distribution of minimum dihedral angles than regular background meshes, facilitating the optimization procedures that rely on previously defined tetrahedral meshes. In addition, these background meshes can reduce(More)
We describe a free-form stroke-based modeling system where objects are primarily represented by means of variational surfaces. Although similar systems have been described in recent years, our approach achieves both a good performance and reduced surface leak problems by employing a coarse mesh as support for constraint points. The prototype implements an(More)
This paper presents a description of the reorganization of a geometric modeler, MG, designed to support new capabilities of a topological module (CGC) that allows the detection of closed-off solid regions described by surface patches in non-manifold geometric models defined by NURBS. These patches are interactively created by the user by means of the(More)