A Review of Digital Terrain Modeling

Abstract

Terrains are a crucial component of three‐dimensional scenes and are present in many Computer Graphics applications. Terrain modeling methods focus on capturing landforms in all their intricate detail, including eroded valleys arising from the interplay of varied phenomena, dendritic mountain ranges, and complex river networks. Set against this visual complexity is the need for user control over terrain features, without which designers are unable to adequately express their artistic intent. This article provides an overview of current terrain modeling and authoring techniques, organized according to three categories: procedural modeling, physically‐based simulation of erosion and land formation processes, and example‐based methods driven by scanned terrain data. We compare and contrast these techniques according to several criteria, specifically: the variety of achievable landforms; realism from both a perceptual and geomorphological perspective; issues of scale in terms of terrain extent and sampling precision; the different interaction metaphors and attendant forms of user‐control, and computation and memory performance. We conclude with an in‐depth discussion of possible research directions and outstanding technical and scientific challenges.

Procedural Method for Fast Table Mountains Modelling in Virtual Environments

“…The matrices of elevation values i.e., height fields are the simplest and most commonly used for terrain models. This is due to the ease of implementation of procedural methods for generating and rendering synthetic landforms [9,[15][16][17][18]. The main disadvantage of this representation is the inability to replicate models with aspherical topology [19].…”

“…Hybrid methods can be also isolated by trying to cumulate positive aspects of both main representations, while minimising their weaknesses. Beneš and Forsbach introduced layered representation consisting of stacked horizontal materials, where each has its own elevation and geological attributes [8,15,16,18].…”

“…Since the works of Mandelbrot, fractal geometry plays an important role in computer-assisted terrain modelling [18,[20][21][22]. Fractal based terrains range from the basic self-similar, noise-based structures to more naturally eroded landforms expanded by rivers and coastlines [9,10,[23][24][25][26][27][28].…”

“…The method is not intended to simulate dynamic, complex, and time-consuming erosive processes, but the effects they cause is directed for artist and designers, so as to quickly provide assets for further use. In the proposed solution, a terrain model is layered [8], represented by classic height-field [15,16,18] extended by information about distribution and hardness of the materials. The method is based on fractal geometry [22] and modified by the Poisson Faulting algorithm [40], whereby the geometry layer is obtained.…”

“…The first is a geometric layer. It is related to a classic height-field and holds geometric data of the landform and can be defined as a function g: R 2 → R [18]. The second is a materials layer.…”