Examinando por Autor "Lalinde, Juan G."

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    Ítem
    A curvature-sensitive parameterization-independent triangulation algorithm
    (2008-09) Ruíz, Óscar; Congote, John; Cadavid, Carlos; Lalinde, Juan G.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Triangulations of a connected subset F of parametric surfaces S(u,v) (with continuity C2 or higher) are required because a C0 approximation of such F(called a FACE) is widely required for finite element analysis, rendering, manufacturing, design, reverse engineering, etc -- The triangulation T is such an approximation, when its piecewise linear subsets are triangles (which, on the other hand, is not a compulsory condition for being C0) -- A serious obstacle for algorithms which triangulate in the parametric space u−v is that such a space may be extremely warped, and the distances in parametric space be dramatically different of the distances in R3 -- Recent publications have reported parameter -independent triangulations, which triangulate in R3 space -- However, such triangulations are not sensitive to the curvature of the S(u,v) -- The present article presents an algorithm to obtain parameter-independent, curvature-sensitive triangulations -- The invariant of the algorithm is that a vertex v of the triangulation if identified, and a quasiequilateral triangulation around v is performed on the plane P tangent to S(u,v) at v -- The size of the triangles incident to v is a function of K(v), the curvature of S(u,v) at v -- The algorithm was extensively and successfully tested, rendering short running times, with very demanding boundary representations
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    Ítem
    Gabriel-constrained Parametric Surface Triangulation
    (2008-10) Ruíz, Óscar E.; Cadavid, Carlos; Lalinde, Juan G.; Serrano, Ricardo; Peris-Fajarnés, Guillermo; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    The Boundary Representation of a 3D manifold contains FACES (connected subsets of a parametric surface S : R2−R3) -- In many science and engineering applications it is cumbersome and algebraically difficult to deal with the polynomial set and constraints (LOOPs) representing the FACE -- Because of this reason, a Piecewise Linear (PL) approximation of the FACE is needed, which is usually represented in terms of triangles (i.e. 2-simplices) -- Solving the problem of FACE triangulation requires producing quality triangles which are: (i) independent of the arguments of S, (ii) sensitive to the local curvatures, and (iii) compliant with the boundaries of the FACE and (iv) topologically compatible with the triangles of the neighboring FACEs -- In the existing literature there are no guarantees for the point (iii) -- This article contributes to the topic of triangulations conforming to the boundaries of the FACE by applying the concept of parameter independent Gabriel complex, which improves the correctness of the triangulation regarding aspects (iii) and (iv) -- In addition, the article applies the geometric concept of tangent ball to a surface at a point to address points (i) and (ii) -- Additional research is needed in algorithms that (i) take advantage of the concepts presented in the heuristic algorithm proposed and (ii) can be proved correct