A Survey of Procedural Techniques for City Generation

The computer game industry requires a skilled workforce and this combined with the complexity of modern games, means that production costs are extremely high. One of the most time consuming aspects is the creation of game geometry, the virtual world which the players inhabit. Procedural techniques have been used within computer graphics to create natural textures, simulate special effects and generate complex natural models including trees and waterfalls. It is these procedural techniques that we intend to harness to generate geometry and textures suitable for a game situated in an urban environment. Procedural techniques can provide many benefits for computer graphics applications when the correct algorithm is used. An overview of several commonly used procedural techniques including fractals, L-systems, Perlin noise, tiling systems and cellular basis is provided. The function of each technique and the resulting output they create are discussed to better understand their characteristics, benefits and relevance to the city generation problem. City generation is the creation of an urban area which necessitates the creation of buildings, situated along streets and arranged in appropriate patterns. Some research has already taken place into recreating road network patterns and generating buildings that can vary in function and architectural style. We will study the main body of existing research into procedural city generation and provide an overview of their implementations and a critique of their functionality and results. Finally we present areas in which further research into the generation of cities is required and outline our research goals for city generation

Procedurally generated realistic virtual rural worlds

Manually creating virtual rural worlds is often a difficult and lengthy task for artists, as plant species selection, plant distributions and water networks must be deduced such that they realistically reflect the environment being modelled. As virtual worlds grow in size and complexity, climates vary on the terrain itself and a single ecosystem is no longer sufficient to realistically model all vegetation. Consequentially, the task is only becoming more difficult for these artists. Procedural methods are extensively used in computer graphics to partially or fully automate some tasks and take some of the burden off the user. Input parameters for these procedural algorithms are often unintuitive, however, and their impact on the final results, unclear. This thesis proposes, implements, and evaluates an approach to procedurally generate vegetation and water networks for realistic virtual rural worlds. Rather than placing these to reflect the environment being modelled, the work-flow is mirrored and the user models the environment directly by specifying the resources available. These intuitive input parameters are subsequently used to configure procedural algorithms and determine suitable vegetation, plant distributions and water networks. By design, the placeable plant species are configurable so any type of environment can be modelled at various levels of detail. The system has been tested by creating three ecosystems with little effort on the part of the user

Stylised procedural animation

This thesis develops a stylised procedural paradigm for computer graphics animation. Cartoon effects animations - stylised representations of natural phenomena - have presented a long-standing, difficult challenge to computer animators. We propose a framework for achieving the intricacy of effects motion with minimal animator intervention.Our approach is to construct cartoon effects by simulating the hand-drawing process through synthetic, computational means. We create a system which emulates the stylish appearance, movements of cartoon effects in both 2D and 3D environments. Our computational models achieve this by capturing the essential characteristics common to all cartoon effects: structure modelling, dynamic controlling and stylised rendering.To validate our framework, we have implemented a cartoon effects system for a range of effects including water effects, fire, smoke, rain and snow. Each effect model has its own static structure such as how the different parts are related temporarily. The flexibility of our approach is suggested most evidently by the high-level controls on shape, colour, timing and rendering on the effects. Like their hand-drawn counterparts, they move consistently while retaining the hand-crafted look.Since the movements of cartoon effects are animated procedurally, their detailed motions need not be keyframed. This thesis therefore demonstrates a powerful approach to computer animation in which the animator plays the role of a high level controller, rather than the more conventional hand-drawing slave. Our work not only achieves cartoon effects animation of un-precedented complexity, but it also provides an interesting experimental domain for related research disciplines toward more creative and expressive image synthesis in animation

A Parametric Sound Object Model for Sound Texture Synthesis

This thesis deals with the analysis and synthesis of sound textures based on parametric sound objects. An overview is provided about the acoustic and perceptual principles of textural acoustic scenes, and technical challenges for analysis and synthesis are considered. Four essential processing steps for sound texture analysis are identifi ed, and existing sound texture systems are reviewed, using the four-step model as a guideline. A theoretical framework for analysis and synthesis is proposed. A parametric sound object synthesis (PSOS) model is introduced, which is able to describe individual recorded sounds through a fi xed set of parameters. The model, which applies to harmonic and noisy sounds, is an extension of spectral modeling and uses spline curves to approximate spectral envelopes, as well as the evolution of parameters over time. In contrast to standard spectral modeling techniques, this representation uses the concept of objects instead of concatenated frames, and it provides a direct mapping between sounds of diff erent length. Methods for automatic and manual conversion are shown. An evaluation is presented in which the ability of the model to encode a wide range of di fferent sounds has been examined. Although there are aspects of sounds that the model cannot accurately capture, such as polyphony and certain types of fast modulation, the results indicate that high quality synthesis can be achieved for many different acoustic phenomena, including instruments and animal vocalizations. In contrast to many other forms of sound encoding, the parametric model facilitates various techniques of machine learning and intelligent processing, including sound clustering and principal component analysis. Strengths and weaknesses of the proposed method are reviewed, and possibilities for future development are discussed

Retroreflection and waterfalls: speaking and singing in extreme acoustic environments.

This is a cross-disciplinary thesis consisting of both acoustics science research and practice-led research focused on improvised music performance. In very different ways, both types of research focus on how a person’s surrounding environment affects voice production. The thesis describes two experiments: a behavioural laboratory talking experiment and singing practice experiment with research outcomes including an original framework for singing practice and a recorded work of ensemble improvised music. Key aspects of both experiments are (i) vocal production response to the acoustic environment, (ii) acoustics that optimise the environment for a singer or talker, and (iii) the acoustic environment created by a retroreflective array whereby sound is reflected back to the person. The experiments can be summarised as follows: 1. A behavioural laboratory experiment A talking experiment that investigates how the sound of one’s own voice (autophony), with alterations in gain and spectral balance, influences conversational speech production. The experiment addressed the question: can acoustic treatments with a frequency bias, like a retroreflective array, influence voice production, optimising a room for comfortable conversing? 2. A practice-led singing experiment A singing experiment was completed in three stages. Stage one (i) was the design of a practice framework that facilitated the discovery and creative development of singing techniques and musical materials. The design incorporated empirical research about autophony and voice production response to room reflections and environment sound and an approach to skill acquisition based on the ecological dynamics theory called the constraints-led approach. Stage two (ii) was fifteen-months of recorded self-regulated singing practice within the practice framework. Stage three (iii) applied the vocal skills and musical materials discovered and developed in stage two to recorded ensemble improvisation

Content And Multimedia Database Management Systems

A database management system is a general-purpose software system that facilitates the processes of defining, constructing, and manipulating databases for various applications. The main characteristic of the ‘database approach’ is that it increases the value of data by its emphasis on data independence. DBMSs, and in particular those based on the relational data model, have been very successful at the management of administrative data in the business domain. This thesis has investigated data management in multimedia digital libraries, and its implications on the design of database management systems. The main problem of multimedia data management is providing access to the stored objects. The content structure of administrative data is easily represented in alphanumeric values. Thus, database technology has primarily focused on handling the objects’ logical structure. In the case of multimedia data, representation of content is far from trivial though, and not supported by current database management systems

Derivative composition practice & application: creating a collection of works based on electric guitar solos

This thesis concerns itself with the practice I have come to call derivative composition. The process involves taking fragments from earlier compositions and transferring them to form a new piece for a different instrument or ensemble. The differences between the original and target instruments causes deviations to occur. Consequently, these deviations are then used to purposely generate new works instead of arranging them from the old work. This new work then undergoes the derivative process again, generating another new piece. This process repeats deriving new pieces from the previous compositions and forming a series of pieces resembling a family tree. To explore the generative properties of derivative composition I begin with my own original pieces for solo electric guitar. The idiosyncrasies of various technical innovations create a significant number of deviations when transferred to very different instrumental forces, allowing the generation of new works. This thesis and commentary will be useful to composers interested in recomposition as well as performers/composers interested in using their instruments as a catalyst for compositions for other instruments, and vice versa. Other instruments might be the impetus for a new work for theirs

THE ART AND SCIENCE OF WOOD: FROM PYROGRAPHY TO TERMITES AND WOOD DECOMPOSITION

Wood is vital to many natural ecosystems, as it provides energy, nutrients, and habitat for organisms from the micro- to the macro- scale. Wood is also critical to humans for similar reasons, and can be an important medium of art and education. This dissertation addresses three diverse aspects of wood with the contexts of science, art, and education. First, we explored the impact of timber harvest techniques and site preparation on microbial wood decay and subterranean termite responses on a forest-stand scale. The amount of coarse woody debris removed post-harvest, coupled with the location and species of the test wood stakes, significantly affected both termite and microbial-mediated decomposition after two and a half years of exposure. These findings help to better understand the impact of timber harvest practices on carbon cycling and associated modes of decay. We then explored effects of wood species and wood surface preparation on pyrography, the art of woodburning. The species of wood and the surface preparation significantly affected line and shading work in pyrography, with more detailed linework produced on hardwoods (Acer rubrum, Populus tremuloides) than on softwoods (Pinus taeda, Pinus strobus). Lastly, placing wood into an educational context, high school level lesson plans that address several science curriculum state and federal benchmarks were developed, to be taught through the active learning technique of pyrography. A general “Introduction to woodburning” lesson plan is included, followed by lesson plans for cellular respiration, human impacts on the environment, photosynthesis, and the carbon cycle. Lesson plans provide instructors with the resources needed to teach across both science and art curriculums. Each lesson plan includes background material, vocabulary, assignments, instructional videos, and PowerPoint presentations. These three chapters weave together science, art, and education using wood as the common thread

Procedural content generation for games

Virtual worlds play an increasingly important role in game development today. Whether in the entertainment industry, education, collaboration or data visualization - virtual space offers a freely definable environment that can be adapted to any purpose. Nevertheless, the creation of complex worlds is time-consuming and cost-intensive. A classic example for the use of a virtual world is a driving simulator where learner drivers can test their skills. The goal of the generation process is to model a realistic city that is large enough to move around for a long time without constantly passing places that have already been seen. Streets must be realistically modeled, have intersections, represent highways and country roads and create an image through buildings that create the greatest possible immersion in the virtual world. But there is still a lack of life. Pedestrians have to populate the streets in large numbers, other cars have to take part in the traffic, and a driving instructor has to sit next to the learner driver, commenting on the actions and chatting away on long journeys. In short, the effort to model such a world by hand would be immense. This thesis deals with different approaches to generate digital content for virtual worlds procedurally i.e., algorithmically. In the first part of this thesis, virtual, three-dimensional road networks are generated using a pre-defined network graph. The nodes in the graph can be generated procedurally or randomly or can be imported from open data platforms, e.g., from OpenStreetMaps (OSM). The automatic detection of intersections makes the generation flexible. The textures used for roads and intersections are constructed from prefabricated sprites whenever possible, or, in the case of a very individual construction, are newly generated during generation. The ability to create multi-lane roads gives the virtual cities a higher degree of realism. The interstices of the road network usually contain buildings, industrial areas, common areas or agricultural land. Once these so-called parcels have been identified, they can be populated with precisely these contents. In this dissertation we focus on accessible residential buildings. The second part of this thesis discusses a novel method of building generation that allows to procedurally create walk-in, multi-storey buildings. The proceeding of simple mesh generation as shown in the road network generation is extended by rules and constraints that allow a flexible floor planning and guarantee a connection of all rooms by a common corridor per floor and a staircase. Since a cityscape is usually characterised by different building shapes, the generation can be parameterized with regard to texturing, roof design, number of floors, and window and door layout. In order to ensure performance when rendering the city, each building is generated in three levels of detail. The lowest level only shows the outer walls, the highest level shows the interior rooms including stairs, doors and window frames. Once the environment is created in a way that allows the player a certain immersion, the game world has to be filled with life. Thus, the third part of this thesis discusses the procedural creation of stories for games based on pre-trained language models. The focus here is on an interactive, controlled way of playing, in which the player can interact with the objects, persons and places of the story and influence the plot. Actions generated from the entities of the previous section of the story should give a feeling of a prepared story, but always ensure the greatest possible flexibility of course. The controlled use of places, people and objects in the player's inventory allows a porting to a three-dimensional game world as well as the gameplay in the form of a text adventure. All methods for creating digital content presented in this thesis were fully implemented and evaluated with respect to usability and performance