Fast visibility analysis in 3D procedural modeling environments

Abstract

This paper presents a unique solution to the visibility problem in 3D urban environments generated by procedural modeling. We shall introduce a visibility algorithm for a 3D urban environment, consisting of mass modeling shapes. Mass modeling consists of basic shape vocabulary with a box as the basic structure. Using boxes as simple mass model shapes, one can generate basic building blocks such as L, H, U and T shapes, creating a complex urban environment model computing visible parts. Visibility analysis is based on an analytic solution for basic building structures as a single box. A building structure is presented as a continuous parameterization approximating of the building's corners. The algorithm quickly generates the visible surfaces' boundary of a single building and, consequently, its visible pyramid volume. Using simple geometric operations of projections and intersections between these visible pyramid volumes, hidden surfaces between buildings are rapidly computed. Real urban environment from Boston, MA, approximated to the 3D basic shape vocabulary model demonstrates our approach.

Tecnologias da informação aplicadas à avaliação da visibilidade de bens tombados em contextos urbanos | Information technologies applied to the assessment of the visibility of historical heritage in urban contexts

“…Em Fisher-Gewirtzman & Wagner (2003), Fisher-Gewirtzman, Shach Pinsly, Wagner & Burt (2005), Yang, Putra & Li (2007), Gal & Doytsher (2012), Suleiman, Joliveau & Favier (2013) e Koltsova, Tunçer & Schmitt (2013) encontramos importantes contribuições que expandem o modelo bidimensional para um ambiente tridimensional, retornando ao conceito original proposto por Benedikt (1979) que, apesar de ter se utilizado de diagramas em planta baixa, alertava para a tridimensionalidade do fenômeno.…”

Fast and efficient visible trajectories planning for the Dubins UAV model in 3D built-up environments

“…Our 3D model can be easily generated from available data, such as Google Map. 3 We assume that the model is uploaded to the UAV computer offline before starting mission.…”

“…More complex building models can be subdivided to basic box structures using procedural modeling and basic shape grammar profiles. 3 The intersection of VPs allows us to efficiently compute the hidden surfaces in urban environments, as can be seen in the next subsection.…”

“…Simulation results for a number of urban scenes and mass modeling complex urban environments visibility can be found in refs. [2,3].…”

“…1 The spatial relationship between different objects is computed by using fast visible pyramid (VP) volumes from the viewpoint, projected to the occluded buildings. 2,3 We present a local UAV trajectory planner that generates one step ahead every time step, which takes into account kinematic and dynamic constraints modeling UAV trajectories with the Dubins airplane model for time-optimal trajectories. For the first time, this planner generates fast and exact visible trajectories, based on the analytic solution described above.…”