18 research outputs found
Relief impostor selection for large scale urban rendering
Image-based rendering techniques are often the preferred choice to accelerate the exploration of massive outdoor models and complex human-made structures. In the last few years, relief mapping has been shown to be extremely useful as a compact representation of highly-detailed 3D models. In this paper we describe a rendering system for interactive, high-quality visualization of large scale urban models through a hierarchical collection of properly-oriented
relief-mapped polygons. At the heart of our approach is a visibilityaware algorithm for the selection of the set of viewing planes supporting the relief maps. Our selection algorithm optimizes both the sampling density and the coverage of the relief maps and its running time is mostly independent on the underlying geometry. We show that our approach is suitable for navigating through large scale urban models at interactive rates while preserving both geometric and
appearance details.Postprint (published version
Interactive inspection of complex multi-object industrial assemblies
The final publication is available at Springer via http://dx.doi.org/10.1016/j.cad.2016.06.005The use of virtual prototypes and digital models containing thousands of individual objects is commonplace in complex industrial applications like the cooperative design of huge ships. Designers are interested in selecting and editing specific sets of objects during the interactive inspection sessions. This is however not supported by standard visualization systems for huge models. In this paper we discuss in detail the concept of rendering front in multiresolution trees, their properties and the algorithms that construct the hierarchy and efficiently render it, applied to very complex CAD models, so that the model structure and the identities of objects are preserved. We also propose an algorithm for the interactive inspection of huge models which uses a rendering budget and supports selection of individual objects and sets of objects, displacement of the selected objects and real-time collision detection during these displacements. Our solution–based on the analysis of several existing view-dependent visualization schemes–uses a Hybrid Multiresolution Tree that mixes layers of exact geometry, simplified models and impostors, together with a time-critical, view-dependent algorithm and a Constrained Front. The algorithm has been successfully tested in real industrial environments; the models involved are presented and discussed in the paper.Peer ReviewedPostprint (author's final draft
Relief mapping on cubic cell complexes
In this paper we present an algorithm for parameterizing arbitrary surfaces onto a quadrilateral domain defined by a collection of cubic cells. The parameterization inside each cell is implicit and thus requires storing no texture coordinates. Based upon this parameterization, we propose a unified representation of geometric and appearance information of complex models. The representation consists of a set of cubic cells (providing a coarse representation of the object) together with a collection of distance maps (encoding fine geometric detail
inside each cell). Our new representation has similar uses than geometry images, but it requires storing a single distance value per texel instead of full vertex coordinates. When combined with color and normal maps, our representation can be used to render an approximation of the model through an output-sensitive relief mapping
algorithm, thus being specially amenable for GPU raytracing.Postprint (author’s final draft
La realidad virtual en el aprendizaje de historia mediante la interacción con humanoides virtuales
La realidad virtual ofrece la posibilidad de interactuar de manera inmersiva en mundos virtuales 3D. Estos mundos virtuales pueden ser representaciones de otros momentos históricos que permiten al usuario explorar
los modelos virtuales como si de una visita turística al pasado se tratase. En este proyecto se ha realizado una reconstrucción virtual de la antigua ciudad romana de Tarragona (Tarraco) para ofrecer un entorno interactivo en el que los visitantes a la exposición puedan navegar por diferentes partes de la ciudad así como interactuar con humanoides virtuales representando romanos que ayudarán al usuario a recopilar información histórica y aprender mediante un
sencillo juego interactivo.Peer ReviewedPostprint (author’s final draft
Output-Sensitive Rendering of Detailed Animated Characters for Crowd Simulation
High-quality, detailed animated characters are often represented as textured
polygonal meshes. The problem with this technique is the high cost
that involves rendering and animating each one of these characters. This
problem has become a major limiting factor in crowd simulation. Since we
want to render a huge number of characters in real-time, the purpose of
this thesis is therefore to study the current existing approaches in crowd
rendering to derive a novel approach.
The main limitations we have found when using impostors are (1) the
big amount of memory needed to store them, which also has to be sent
to the graphics card, (2) the lack of visual quality in close-up views, and
(3) some visibility problems. As we wanted to overcome these limitations,
and improve performance results, the found conclusions lead us to present
a new representation for 3D animated characters using relief mapping, thus
supporting an output-sensitive rendering.
The basic idea of our approach is to encode each character through a
small collection of textured boxes storing color and depth values. At runtime,
each box is animated according to the rigid transformation of its associated
bone in the animated skeleton. A fragment shader is used to recover
the original geometry using an adapted version of relief mapping. Unlike
competing output-sensitive approaches, our compact representation is able
to recover high-frequency surface details and reproduces view-motion parallax
e ects. Furthermore, the proposed approach ensures correct visibility
among di erent animated parts, and it does not require us to prede ne the
animation sequences nor to select a subset of discrete views. Finally, a user
study demonstrates that our approach allows for a large number of simulated
agents with negligible visual artifacts
Output-Sensitive Rendering of Detailed Animated Characters for Crowd Simulation
High-quality, detailed animated characters are often represented as textured
polygonal meshes. The problem with this technique is the high cost
that involves rendering and animating each one of these characters. This
problem has become a major limiting factor in crowd simulation. Since we
want to render a huge number of characters in real-time, the purpose of
this thesis is therefore to study the current existing approaches in crowd
rendering to derive a novel approach.
The main limitations we have found when using impostors are (1) the
big amount of memory needed to store them, which also has to be sent
to the graphics card, (2) the lack of visual quality in close-up views, and
(3) some visibility problems. As we wanted to overcome these limitations,
and improve performance results, the found conclusions lead us to present
a new representation for 3D animated characters using relief mapping, thus
supporting an output-sensitive rendering.
The basic idea of our approach is to encode each character through a
small collection of textured boxes storing color and depth values. At runtime,
each box is animated according to the rigid transformation of its associated
bone in the animated skeleton. A fragment shader is used to recover
the original geometry using an adapted version of relief mapping. Unlike
competing output-sensitive approaches, our compact representation is able
to recover high-frequency surface details and reproduces view-motion parallax
e ects. Furthermore, the proposed approach ensures correct visibility
among di erent animated parts, and it does not require us to prede ne the
animation sequences nor to select a subset of discrete views. Finally, a user
study demonstrates that our approach allows for a large number of simulated
agents with negligible visual artifacts