In this paper, we present a simple technique to evaluate the visibility between pairs of points in a scene. In most current rendering algorithms, visibility queries are evaluated exactly. Our approach approximates the visibility value between two points using a point cloud representation of the surfaces in the scene. The computed value is a function of the distance and orientation of points in ...

Dense forests are discrete subsets of Euclidean space which uniformly close to all sufficiently long line segments. The degree density a dense forest is measured by its visibility function. We show that cut-and-project quasicrystals never forests, but their finite unions could be forests. On the other hand, we lattices typically and give bound on function, optimal. also construct an explicit un...

The efficient evaluation of visibility in a three-dimensional scene is a longstanding problem in computer graphics. Visibility evaluations come in many different forms: figuring out what object is visible in a pixel; determining whether a point is visible to a light source; or evaluating the mutual visibility between 2 surface points. This paper provides a new, experimental view on visibility, ...

Given a collection of polygonal obstacles with n vertices on the place, and any t > 1, we present an O(n logn) time algorithm that constructs a bounded-degree t-spanner of the visibility graph, without rst having to construct the visibility graph.

Air pollution from motor vehicles, electricity-generating plants, industry, and other sources can harm human health, injure crops and forests, damage building materials, and impair visibility. Economists sometimes analyze the social cost of these impacts, in order to illuminate tradeoffs, compare alternatives, and promote efficient use of scarce resource. In this paper, we compare estimates of ...

hyperactivity disorder (ADHD) Ainara Mira-Iglesias; J. Alberto Conejero; Esperanza Navarro-Pardo Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Valencia, Spain Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Spain Departamento de Psicoloǵıa Evolutiva y de la Educación, Universitat de València,...

A polyhedral terrain is the graph of a continuous piecewise linear function defined over the triangles of a triangulation in the xy-plane. Two points on or above a terrain are visible to each other if the line-of-sight does not intersect the space below the terrain. In this paper, we look at three related visibility problems in terrains. Suppose we are given a terrain T with n triangles and two...

At each shade point, the spherical visibility function encodes occlusion from surrounding geometry, in all directions. Computing this function is difficult and point-sampling approaches, such as ray-tracing or hardware shadow mapping, are traditionally used to efficiently approximate it. We propose a semi-analytic solution to the problem where the spherical silhouette of the visibility is compu...

Due to 3D occlusion, the specification of proper opacities in direct volume rendering is a time-consuming and unintuitive process. The visibility histograms introduced by Correa and Ma reflect the effect of occlusion by measuring the influence of each sample in the histogram to the rendered image. However, the visibility is defined on individual samples, while volume exploration focuses on conv...