Examinando por Autor "Posada, J."

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    Interactive visualization of volumetric data with WebGL in real-time
    (2011-01-01) Congote, J.; Segura, A.; Kabongo, L.; Moreno, A.; Posada, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    This article presents and discusses the implementation of a direct volume rendering system for the Web, which articulates a large portion of the rendering task in the client machine. By placing the rendering emphasis in the local client, our system takes advantage of its power, while at the same time eliminates processing from unreliable bottlenecks (e.g. network). The system developed articulates in efficient manner the capabilities of the recently released WebGL standard, which makes available the accelerated graphic pipeline (formerly unusable). The dependency on specially customized hardware is eliminated, and yet efficient rendering rates are achieved. The Web increasingly competes against desktop applications in many scenarios, but the graphical demands of some of the applications (e.g. interactive scientific visualization by volume rendering), have impeded their successful settlement in Web scenarios. Performance, scalability, accuracy, security are some of the many challenges that must be solved before visual Web applications popularize. In this publication we discuss both performance and scalability of the volume rendering by WebGL ray-casting in two different but challenging application domains: medical imaging and radar meteorology. © 2011 ACM.
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    Marching cubes in an unsigned distance field for surface reconstruction from unorganized point sets
    (INSTICC-INST SYST TECHNOLOGIES INFORMATION CONTROL & COMMUNICATION, 2010-01-01) Congote, J.; Moreno, A.; Barandiaran, I.; Barandiaran, J.; Posada, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Surface reconstruction from unorganized point set is a common problem in computer graphics. Generation of the signed distance field from the point set is a common methodology for the surface reconstruction. The reconstruction of implicit surfaces is made with the algorithm of marching cubes, but the distance field of a point set can not be processed with marching cubes because the unsigned nature of the distance. We propose an extension to the marching cubes algorithm allowing the reconstruction of 0-level iso-surfaces in an unsigned distance field. We calculate more information inside each cell of the marching cubes lattice and then we extract the intersection points of the surface within the cell then we identify the marching cubes case for the triangulation. Our algorithm generates good surfaces but the presence of ambiguities in the case selection generates some topological mistakes.
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    ReWeb3D - Enabling desktop 3D applications to run in the web
    (2013-01-01) Glander, T.; Moreno, A.; Aristizabal, M.; Congote, J.; Posada, J.; Garcia-Alonso, A.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Currently, 3D rendering is accessible within Web browsers through open standards such as WebGL, X3D, and X3DOM. At the same time, there is wealth of mature desktop software which comprises algorithms, data structures, user interfaces, databases, etc. It is a challenge to reuse such desktop software using the Web visualization resources. In response to this challenge, this article presents a novel framework, called ReWeb3D, which minimizes the redevelopment for migration of existing 3D applications to the Web. The redeployed application runs on a Web server. ReWeb3D captures low-level graphic calls including geometry, texture, and shader programs. The captured content is then served as a WebGL-enabled web page that conveys full interactivity to the client. By splitting the graphics pipeline between client and server, the workload can be balanced, and high-level implementation details and 3D content are hidden. The feasibility of ReWeb3D has been tested with applications which use OpenSceneGraph as rendering platform. The approach shows good results for applications with large data sets (e.g. geodata), but is less suited for applications intensive in animations (e.g. games). Copyright © ACM 978-1-4503-2133-4/13/06 $15.00.