Abstract
The virtual environments used in scientific driving simulation experiments require extensive 3D models of road landscapes, correctly modeled and similar to those found in the real world. The modeling task of these environments, addressing the terrain definition and the specific characteristics required by the target applications, may result in a complex and time-consuming process. This chapter presents a procedural method to model large terrain definitions and adjust the roadside landscape to produce well-constructed road environments. The proposed procedural method allows merging an externally modeled road into a terrain definition, providing an integrated generation of driving environments. The road and terrain models are optimized to interactive visualization in real time, by applying most state-of-art techniques like the level of detail selection and spatial hierarchization. The proposed method allows modeling large road environments, with the realism and quality required to perform experimental studies in driving simulators.
TopState Of Art
To generate virtual road environments, that fit the realism imposed for scientific driving simulation applications, a terrain model definition is required, where the road network can be implemented (Campos, Leitão, & Coelho, 2014; Campos, Leitão, Pereira, Ribas, & Coelho, 2015b; Campos, Leitão, & Coelho, 2015c). To generate terrain model definitions, typically known as digital elevation maps (DEM), several approaches have been suggested and developed. Although most known methods are suitable to generate terrains that can be used in several simulation applications, most of them do not allow the correct adjustment of the terrain required after imposing an externally designed road.
DEMs can be defined as a two-dimensional grid where each cell contains an elevation value and are the most used representation of terrains. Among the classical techniques for generating elevation maps are techniques based on subdivision and techniques based on noise generators (Miller, 1986; Fournier, Fussell, & Carpenter, 1982; Musgrave, Kolb, & Mace, 1989). The result is a mountainous terrain with a natural appearance.
Key Terms in this Chapter
Procedural Modeling: A technique used in computer graphics to automate the creation of 3D models from sets of rules or algorithms.
Terrain Erosion: The evolutive process of changing the shape of terrain due to wind, water, or other natural agents.
Road Network: A set of intersecting roads and their interconnections allowing the selection of several different travel paths between the start and end points.
3D Model: A software representation of a three-dimensional element, mainly concerning the object geometry but can also address many other properties.
Embankment and Cut Slope: Terrain hills located on the side of the road that can be natural or artificial made during the road construction.
Driving Environment: A real or virtual world used to conduct driving tasks, including a road network, road side elements, landscapes and other vehicles or participants.
Scientific Driving Simulation: A fully parametrizable and controllable simulation of a car driving task, aimed to conduct scientific studies about vehicle performance, road design or driver behavior.