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Now showing 1 - 6 of 6
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    Visual Language Generalization for Procedural Modeling of Buildings
    (The Eurographics Association, 2012) Barroso, Santiago; Patow, Gustavo; Isabel Navazo and Gustavo Patow
    Procedural modeling has become the accepted standard for the creation of detailed large scenes, in particular urban landscapes. With the introduction of visual languages there has been a huge leap forward in terms of usability, but there is still need of more sophisticated tools to simplify the development process. In this paper we present extensions to the visual modeling of procedural buildings, which adapt concepts from general purpose programming languages, with the objective of providing higher descriptive power. In particular, we present the concepts of visual modules, parameter linking and the possibility to seamlessly add abstract parameter templates to the designer visual toolbox. We base our demonstrations on a new visual language created for volume-based models like historic architectonic structures (aqueducts, churches, cathedrals, etc.), which cannot be modeled as 2D facades because of the intrinsic volumetric structure of these construction (e.g. vaults or arches).
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    A Procedural Modeling System for the Creation of Huge Models
    (The Eurographics Association, 2012) Cubero, Francisco; Mas, Albert; Patow, Gustavo; Isabel Navazo and Gustavo Patow
    This paper presents a new general purpose procedural geometrical modeling system. It is focused on providing flexibility, modularity and scalability. Furthermore, it is taylored to manage huge geometric models, with millions of polygons. An out-of-core memory management system assures that any scene size can be generated during the modeling evolution. This generation is performed by a set of rules and operations on geometrical objects, organized as a directed acyclic graph.
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    Simulation of the Commercial Market Evolution in a City
    (The Eurographics Association, 2015) Soriano, Carlos; Patow, Gustavo; Mateu Sbert and Jorge Lopez-Moreno
    Simulating the evolution of urban landscapes is a challenging objective with a large impact not only for Computer Graphics (for its applications in the filming and gaming industries), but also for urban planning, economical and historical studies, urban physics, and many other. However, this target has remained elusive because of the large complexity implied by urban structures and their evolutions. We present a system that aims at simulating the evolution of the commercial structure in a modern city. In particular, given an initial distribution of shops, it studies the evolution when larger commercial areas, like malls, are introduced. This is computed using the Huff model as a measure of the attraction each commerce has on potential consumers, and an agent-based simulation to determine how these aspects affect their choices. Then, after a given simulation time, the system decides whether the shop has retained an income such that it can continue operating, or has gone bankrupt. Our system is used to study the evolution of the commercial structure of Barcelona city over the last century. 1. Introduction Procedural urban modeling has presented us with astonishing results over the last decade, starting with the seminal work by Parish and Muller [PM01] and Muller et al. [MWH 06], and continuing with the recent advances in acquisition [MWA 12], non-regular modeling [LCOZ 11], user interfaces [Pat12], among others. However, in spite of all those improvements, several problems remain open [PBP14], one of the most important ones is simulating the evolution of urban landscapes over time. With only a few exceptions [WMWG09,BWK14], this topic has barely been touched, in spite of its crucial importance for history and archeology, urban planning, socio-economical studies, and many other social-related disciplines. Among these unexplored aspects, the problem of simulating the evolution of the commerce structure in a city is a prominent one, as it is attractive for being computationally tractable and crucial for socio-economic studies. But this study has applications that are broader than a pure social analysis, as the resulting distributions can be used to also model its appearance over time, which is interesting for computer graphics because of its applications to film and videogames, two of the leading industries in the field. y carlos.
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    Easy Going Vector Graphics as Textures on the GPU
    (The Eurographics Association, 2015) Patow, Gustavo; Mateu Sbert and Jorge Lopez-Moreno
    One common problem of raster images when used as textures is its resolution dependence, which could produce artifacts such as blurring. On the contrary, vector graphics are resolution independent, and their direct use for real-time texture mapping would be desirable to avoid sampling artifacts. Usually, they composite images from layers of paths and strokes defined with different kinds of lines. Here I present a simple yet powerful technique for representing vector graphics as textures that organizes the graphic into a coarse grid of cells, structuring each cell into simple cell-sized BSP trees, evaluated at runtime within a pixel shader. Advantages include coherent low-bandwidth memory access and, although my implementation is limited to polygonal shapes, the ability to map general vector graphics onto arbitrary surfaces. A fast construction algorithm is presented, and the space and time efficiency of the representation are demonstrated on many practical examples.
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    Bringing Direct Local Control to Interactive Visual Editing of Procedural Buildings
    (The Eurographics Association, 2012) Riu, Adria; Patow, Gustavo; Isabel Navazo and Gustavo Patow
    This paper presents a new system to add direct and persistent local control to the visual editing of rules for procedural buildings, avoiding a combinatorial explosion of grammar rules. In this paper we follow the ideas initially proposed by Lipp and co-workers [LWW08]. For this, we have added a few simple new commands, which are added to the artist-provided ruleset in a way completely transparent to the user. The end-user selects the primitives/assets to modify, and the system automatically incorporates these modifications into the ruleset. This change is performed using graph-rewriting techniques, which are both simple to define and control, but also very powerful and practical for these situations.
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    Fast Inverse Reflector Design (FIRD)
    (The Eurographics Association, 2008) Mas, Albert; Martin, Ignacio; Patow, Gustavo; Luis Matey and Juan Carlos Torres
    This paper presents a new method ofr a GPU-based computation of outgoing light distribution for inverse reflector design. We propose a fast method to obtain the outgoing light distribution of a parametrized reflector, and compare it with the desired illumination, that works completely in the GPU. We trace millions of rays using a hierarchical height-field representation of the reflector. Multiple reflections are taken into account. The parameters that define the reflector shape are optimized in an iterative procedure in order that the resulting light distribution is as close as possible to the user-provided target light distribution. We show that our method can calculate the reflector lighting at least one order of magnitude faster, even with millions of rays, and complex geometries and light sources.