Terrain Synthesis Research Articles

Evaluation and Implementation of Landscape Aesthetics Based on Cloud and Edge Computing

People’s aesthetic requirements for landscape environment are improving, and we can also see very beautiful as well as characteristic urban parks, street side green areas and scenic spots with certain aesthetic value around us, and we can find that people’s demand for the living environment they live in regarding beauty is also strengthening. The synergistic development of edge computing and cloud computing is an important development trend in the future, and integrating them into landscape design is an inevitable choice and requirement for developing gardens and building a beautiful China. Based on this, this study first proposes a methodological framework based on machine learning to model and predict GSS, and then proposes a data-driven multi-style terrain synthesis method. The experimental results prove that the optimized landscape perception model optimizes the landscape path aesthetics according to the relevant theories and actual cases of landscape planning and construction.

Authoring Terrains with Spatialised Style

AbstractVarious terrain modelling methods have been proposed for the past decades, providing efficient and often interactive authoring tools. However, they seldom include any notion of style, which is critical for designers in the entertainment industry. We introduce a new generative network method that bridges the gap between automatic terrain synthesis and authoring, providing a versatile set of authoring tools allowing spatialised style. We build upon the StyleGAN2 architecture and extend it with authoring tools. Given an input sketch or existing elevation map, our method generates a terrain with features that can be authored, enhanced, and augmented using interactive brushes and style manipulation tools. The strength of our approach lies in the versatility and interoperability of the different tools. We validate our method quantitatively with drainage calculation against other previous techniques and qualitatively by asking users to follow a prompt or freely create a terrain.

Agent-Based Music Live Coding: Sonic adventures in 2D

This article describes agent-based music live coding, an approach for music performance and composition based on programming a set of agents in a 2D plane. This style of programming draws from the tradition of agent-based models and facilitates interactive algorithmic control of data-driven sound synthesis methods such as wave terrain synthesis or corpus-based concatenative synthesis. The main elements are a ‘terrain’, which may be used to access different types of data, a set of agents and their trajectories, and a set of synthesis functions associated to agents. An implementation using the SuperCollider language is demonstrated.

Identifying key channel variability functions controlling ecohydraulic conditions using synthetic channel archetypes

AbstractGeometric modelling of river channel topography is a method of design synthesis wherein specific 2D geometric elements of river topography, such as the bed profile, cross‐sectional shape and channel planform contours, are expressed mathematically in isolation and then combined to produce a 3D heightmap. We utilized the geometric modelling framework to synthesize channel terrains that reveal flow–form–function linkages to investigate what roles variability in bed roughness, thalweg elevation and channel width play in defining hydraulic and ecohydraulic conditions of a channel reach from baseflow to bankfull discharge. To achieve a robust inquiry for a range of settings, this study developed four distinct synthetic channel terrain models for each of three stream reaches of different channel types in the South Fork Eel River in northern coastal California, USA. To test the process‐based effects of these diverse terrain synthesis options, we compared the resulting hydraulic patterns and preferred habitat availability for fry/juvenile steelhead trout and coho salmon over a range of discharges. Among thalweg bed undulation, width variation and bed roughness, we found thalweg bed undulation was the key factor affecting the channel ecohydraulic response at baseflow condition. At bankfull condition, thalweg bed elevation had the largest effect in high‐order mainstem streams identified by gravel‐cobble dominated high width‐to‐depth, riffle‐pool sequences, width variation had the largest effect in mid‐order confined channels with gravel‐cobble, high width‐to‐depth ratio with expansions/contractions and bed roughness in low‐order streams with low width‐to‐depth ratio, high‐gradient, cobble‐boulder and step‐pool/cascade channels.

Evaluating Realism in Example-based Terrain Synthesis

We report two studies that investigate the use of subjective believability in the assessment of objective realism of terrain. The first demonstrates that there is a clear subjective feature bias that depends on the types of terrain being evaluated: Our participants found certain natural terrains to be more believable than others. This confounding factor means that any comparison experiment must not ask participants to compare terrains with different types of features. Our second experiment assesses four methods of example-based terrain synthesis, comparing them against each other and against real terrain. Our results show that, while all tested methods can produce terrain that is indistinguishable from reality, all also can produce poor terrain; that there is no one method that is consistently better than the others; and that those who have professional expertise in geology, cartography, or image analysis are better able to distinguish real terrain from synthesized terrain than the general population, but those who have professional expertise in the visual arts are not.

Example-based terrain synthesis with pit removal

Artificial terrain synthesis is challenging because natural terrain contains many types of features generated by a diverse range of natural processes over vastly different time-scales. Example-based terrain synthesis has been used to overcome the challenge by using real-world terrain as the basis for synthesis. This produces good local behaviour but can have poor global behaviour. We introduce fluid-flow solutions that can be overlaid on multi-resolution example-based terrain synthesis to improve global realism. We apply these to an existing pixel-based terrain synthesis method and to a novel terrain synthesis method, terrain optimisation, based on texture optimisation. Our fluid-flow solutions improve results for artificial terrains.

Terrain Elevation Map Synthesis Method based on Single Sample and User Sketch

Terrain synthesis has been a hot topic in the field of computer graphics and image processing. However, there are still issues in terrain synthesis where synthesis results are difficult to control and not realistic enough. To address these problems, this paper proposes an interactive terrain elevation map generation method based on the synthesis of a single sample terrain elevation map. First, we propose a method to extract the skeleton from a terrain elevation map and a user sketch. Second, we construct a skeleton sample feature map based on the terrain elevation map and the user sketch. Finally, we propose a matching cost function to match image patches of the terrain sample and the user sketch. The proposed method can obtain a synthesis result containing the features of both the terrain sample and the user sketch, and then generates a synthetic terrain elevation map. The experimental results demonstrate the effectiveness of the proposed method, where the synthesized results can meet the needs of users.

Interactive example-based terrain authoring with conditional generative adversarial networks

Authoring virtual terrains presents a challenge and there is a strong need for authoring tools able to create realistic terrains with simple user-inputs and with high user control. We propose an example-based authoring pipeline that uses a set of terrain synthesizers dedicated to specific tasks. Each terrain synthesizer is a Conditional Generative Adversarial Network trained by using real-world terrains and their sketched counterparts. The training sets are built automatically with a view that the terrain synthesizers learn the generation from features that are easy to sketch. During the authoring process, the artist first creates a rough sketch of the main terrain features, such as rivers, valleys and ridges, and the algorithm automatically synthesizes a terrain corresponding to the sketch using the learned features of the training samples. Moreover, an erosion synthesizer can also generate terrain evolution by erosion at a very low computational cost. Our framework allows for an easy terrain authoring and provides a high level of realism for a minimum sketch cost. We show various examples of terrain synthesis created by experienced as well as inexperienced users who are able to design a vast variety of complex terrains in a very short time.

Terrain Synthesis Guided by Outlines of Mountain Image

Terrain Synthesis Guided by Outlines of Mountain Image

Parallel, Realistic and Controllable Terrain Synthesis

AbstractThe challenge in terrain synthesis for virtual environments is to provide a combination of precise user control over landscape form, with interactive response and visually realistic results.We present a system that builds on parallel pixel‐based texture synthesis to enable interactive creation of an output terrain from a database of heightfield exemplars. We also provide modelers with control over height and surrounding slope by means of constraint points and curves; a paint‐by‐numbers interface for specifying the local character of terrain; coherence controls that allow localization of changes to the synthesized terrain; and copy‐paste functionality to directly transplant terrain regions.Together these contributions provide a level of realism that, based on user experiments, is indistinguishable from real source terrains; user control sufficient for precise placement of a variety of landforms, such as cliffs, ravines and mesas; and synthesis times of 165ms for a 10242 terrain grid.

Controllable and realistic terrain synthesis based on feature sketch and fractal interpolation

Three-dimensional terrain has been used widely in the design and production of virtual outdoor scenes.In order to achieve predictability and controllability of synthesized terrain,a new method for synthesizing realistic terrain was presented based on the controllability of feature sketch and piecing of some hills.Firstly,many hills were generated with different shapes and features by using quadtree structure and improved fractal interpolation method.Then,the required terrain was synthesized by piecing many hills under control of feature sketch.The experimental results show that the method is not only effective and versatile for synthesizing various realistic terrains,but also allow users to control feature and style of synthesized terrain.

Enhanced Texture‐Based Terrain Synthesis on Graphics Hardware

AbstractCurvilinear features extracted from a 2D user‐sketched feature map have been used successfully to constraint a patch‐based texture synthesis of real landscapes. This map‐based user interface does not give fine control over the height profile of the generated terrain. We propose a new texture‐based terrain synthesis framework controllable by a terrain sketching interface. We enhance the realism of the generated landscapes by using a novel patch merging method that reduces boundary artefacts caused by overlapping terrain patches. A more constrained synthesis process is used to produce landscapes that better match user requirements. The high computational cost of texture synthesis is reduced with a parallel implementation on graphics hardware. Our GPU‐accelerated solution provides a significant speedup depending on the size of the example terrain. We show experimentally that our framework is more successful in generating realistic landscapes than current example‐based terrain synthesis methods. We conclude that texture‐based terrain synthesis combined with sketching provides an excellent solution to the user control and realism challenges of virtual landscape generation.

Feature-rich distance-based terrain synthesis

This paper describes a novel terrain synthesis method based on distances in a weighted graph. A height field is determined by least-cost paths in a weighted graph from a set of generator nodes. The shapes of individual terrain features, such as mountains, hills, and craters, are specified by a monotonically decreasing profile describing the cross-sectional shape of a feature. The locations of features in the terrain are specified by placing the generators; secondary ridges are placed by pathing. We show the method to be robust and easy to control, even making it possible to embed images in terrain shadows. The method can produce a wide range of realistic synthetic terrains such as mountain ranges, craters, cinder cones, and hills. The ability to manually place terrain features that incorporate multiple profiles produces heterogeneous terrains that compare favorably to existing methods.

Terrain Synthesis from Digital Elevation Models

In this paper, we present an example-based system for terrain synthesis. In our approach, patches from a sample terrain (represented by a height field) are used to generate a new terrain. The synthesis is guided by a user-sketched feature map that specifies where terrain features occur in the resulting synthetic terrain. Our system emphasizes large-scale curvilinear features (ridges and valleys) because such features are the dominant visual elements in most terrains. Both the example height field and user's sketch map are analyzed using a technique from the field of geomorphology. The system finds patches from the example data that match the features found in the user's sketch. Patches are joined together using graph cuts and Poisson editing. The order in which patches are placed in the synthesized terrain is determined by breadth-first traversal of a feature tree and this generates improved results over standard raster-scan placement orders. Our technique supports user-controlled terrain synthesis in a wide variety of styles, based upon the visual richness of real-world terrain data.

A recursive subdivision scheme for isosurface construction

In the paper, we propose a new method for isosurface construction. We apply a recursive subdivision scheme widely known in fractal terrain synthesis to create a hierarchical mesh over a set of volumetric points. The algorithm starts from an explicit polygonal mesh representing a cube. The main applies a wrapping-like projection in recursive manner with sampling volumetric space along a vector normal in both directions. The algorithm allows for geometry compression and isosurface reconstruction, and follows the idea of the level of detail (LoD). The method is illustrated by example of volumetric escape-time fractals.

Texture synthesis for digital painting

The problem of digital painting is considered from a signal processing viewpoint, and is reconsidered as a problem of directed texture synthesis. It is an important characteristic of natural texture that detail may be evident at many scales, and the detail at each scale may have distinct characteristics. A “sparse convolution” procedure for generating random textures with arbitrary spectral content is described. The capability of specifying the texture spectrum (and thus the amount of detail at each scale) is an improvement over stochastic texture synthesis processes which are scalebound or which have a prescribed 1/f spectrum. This spectral texture synthesis procedure provides the basis for a digital paint system which rivals the textural sophistication of traditional artistic media. Applications in terrain synthesis and texturing computer-rendered objects are also shown.