Real-time crowds significantly improve the realism of virtual environments, therefore their use has increased considerably over the last few years in a variety of applications, including real-time games and virtual tourism. However, due to current hardware limitations, crowd variety tends to be sacrificed in order for the crowd simulation to execute in real-time, which decreases the quality and realism of the crowd. Currently the little variety that is incorporated in real-time crowds tends to be applied by modulating each avatar with random colours, which has a detrimental effect on the texture quality. Furthermore, the existing crowd variety is often hard to define and control. To overcome these problems a set of techniques are presented, which defines and controls crowd variety, to further improve on current variety and quality of crowds. These techniques permit variety to be introduced: by changing the body mass via the application of a displacement map onto the mesh; by scaling the skeleton of the avatar; by applying HSV colour shifts to different parts of the avatar; and by transferring textures between avatar models. The appearance of the avatars under animation is also improved via the use of muscle displacement within the mesh. With the new techniques, the visual quality of the crowd is improved due to the increase in diversity.
[Show abstract][Hide abstract] ABSTRACT: Before an environment can be populated with characters, a set of models
must first be acquired and prepared. Sometimes it may be possible for
artists to create each virtual character individually - for example, if
only a small number of individuals are needed, or there are many artists
available to create a larger population of characters. However, for most
applications that need large and heterogeneous groups or crowds, more
automatic methods of generating large numbers of humans, animals or
other characters are needed. Fortunately, depending on the context, it
is not the case that all types of variety are equally important.
Sometimes quite simple methods for creating variations, which do not
over-burden the computing resources available, can be as effective as,
and perceptually equivalent to, far more resource-intensive approaches.
In this paper, we present some recent research and development efforts
that aim to create and evaluate variety for characters, in their bodies,
faces, movements, behaviours and sounds.
Motion in Games, Second International Workshop, MIG 2009, Zeist, The Netherlands, November 21-24, 2009. Proceedings; 01/2009
[Show abstract][Hide abstract] ABSTRACT: In current computer games and simulation environments, individuality of virtual character bodies are mainly constructed using different textures and accessories. However, this type of modeling generates anthropometrically similar shapes due to the reliance on a single or few body models. Alternatively, using large variety of body size models require larger storage resources and design efforts. We present an efficient method for generating and storing variety of body size models derived from a skinned template. Our method doesn't require additional design efforts and uses the existing skinning data that are already attached to the template model. Algorithm used for sizing the model is based on anthropometric body measurement standards that are used in ergonomic design application. Resulting new body size models use the same skinning information for animation by adapting the underlying skeleton according to the anthropometric parameters. Our developed system is useful in CAD applications from ergonomic design of cloths to parametrically resizing avatars.
Proceedings of the ACM Symposium on Virtual Reality Software and Technology, VRST 2009, Kyoto, Japan, November 18-20, 2009; 01/2009
[Show abstract][Hide abstract] ABSTRACT: Despite its popularity, agent-based modeling is limited by serious barriers that constrain its usefulness as an exploratory tool. In particular, there is a paucity of systematic approaches for extracting coarse-grained, system-level information as it emerges in direct simulation. This is particularly problematic for agent-based models (ABMs) of complex urban systems in which macroscopic phenomena, such as sprawl, may manifest themselves coarsely from bottom-up dynamics among diverse agent-actors interacting across scales. Often these connections are not known, but treating them is nevertheless crucial in enabling prediction, in supporting decisions, and in facilitating the design, control, and optimization of urban systems. In this article, we describe and implement a metasimulation scheme for extracting macroscopic information from local dynamics of agent-based simulation, which allows acceleration of coarse-scale computing and which may also serve as a precursor to handle emergence in complex urban simulation. We compare direct ABM simulation, population-level equation solutions, and coarse projective integration. We apply the scheme to the simulation of urban sprawl from local drivers of urbanization, urban growth, and population dynamics. Numerical examples of the three approaches are provided to compare their accuracy and efficiency. We find that our metasimulation scheme can significantly accelerate complex urban simulations while maintaining faithful representation of the original model.
International Journal of Geographical Information Science 10/2012; 26(10):1-21. DOI:10.1080/13658816.2012.669891 · 1.66 Impact Factor
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