Barbara Yersin

Real-time navigating crowds: Scalable simulation and rendering

This paper introduces a framework for real‐time simulation and rendering of crowds navigating in a virtual environment. The solution first consists in a specific environment preprocessing technique giving rise to navigation graphs, which are then used by the navigation and simulation tasks. Second, navigation planning interactively provides various solutions to the user queries, allowing to spread a crowd by individualizing trajectories. A scalable simulation model enables the management of large crowds, while saving computation time for rendering tasks. Pedestrian graphical models are divided into three rendering fidelities ranging from billboards to dynamic meshes, allowing close‐up views of detailed digital actors with a large variety of locomotion animations. Examples illustrate our method in several environments with crowds of up to 35 000 pedestrians with real‐time performance. Copyright

Populating ancient pompeii with crowds of virtual romans

Pompeii was a Roman city, destroyed and completely buried during an eruption of the volcano Mount Vesuvius. We have revived its past by creating a 3D model of its previous appearance and populated it with crowds of Virtual Romans. In this paper, we detail the process, based on archaeological data, to simulate ancient Pompeii life in real time. In a first step, an annotated city model is generated using procedural modelling. These annotations contain semantic data, such as land usage, building age, and window/door labels. In a second phase, the semantics are automatically interpreted to populate the scene and trigger special behaviors in the crowd, depending on the location of the characters. Finally, we describe the system pipeline, which allows for the simulation of thousands of Virtual Romans in real time.

Challenges in Crowd Simulation

The purpose of this paper is to identify the problems to solve in order to simulate real-time crowds in a Virtual Environment. We try to classify these problems and study how they have been addressed until now by the research community and our Lab in particular. We then discuss for each problem what are the future challenges and how to address them.

Real-Time Scalable Motion Planning for Crowds

Real-time crowd motion planning requires fast, realistic methods for path planning as well as obstacle avoidance. The difficulty to find a satisfying trade-off between efficiency and believability is particularly challenging, and prior techniques tend to focus on a single approach. In this paper, we present a hybrid architecture to handle the path planning of thousands of pedestrians in real time, while ensuring dynamic collision avoidance. The scalability of our approach allows to interactively create and distribute regions of varied interest, where motion planning is ruled by different algorithms. Practically, regions of high interest are governed by a long-term potential field-based approach, while other zones exploit a graph of the environment and short-term avoidance techniques. Our method also ensures pedestrian motion continuity when switching between motion planning algorithms. Tests and comparisons show that our architecture is able to realistically plan motion for many groups of characters, for a total of several thousands of people in real time, and in varied environments.The Voronoi diagram has been investigated intensively throughout the last decades. This has been done not only in the context of Euclidean geometry but also in curved spaces. Except for [KWR97] these methods typically make use of some fast marching cube algorithms. In this work we will focus on the computation of Voronoi diagrams including Voronoi objects that are contained in a Riemannian manifold M. Further, we assume throughout this paper that M has a differentiable structure consisting of smooth parametrisation functions fi, i 2 I. This is the reason why the approach presented in this work differs from the aforementioned algorithms. More accurate algorithms can be obtained by using to some medial equations that heavily involve normal coordinates. This approach relies on the precise computation of shortest joins of any two given points , q 2 M. For these computations we did not apply shooting methods or related methods. Instead, we used a new perturbation method that operates on a family of deformed manifolds Mt, assuming that M0 has constant sectional curvature. To reduce time and space complexity of the introduced algorithm we suggest to use a randomised incremental construction scheme (RICS). Our approach assumes that those points fulfil a general position requirement for computing the geodesic Voronoi diagram for a set of points. Finally results of some computed Voronoi diagrams will be presented.

YaQ: An Architecture for Real-Time Navigation and Rendering of Varied Crowds

The YaQ software platform is a complete system dedicated to real-time crowd simulation and rendering. Fitting multiple application domains, such as video games and VR, YaQ aims to provide efficient algorithms to generate crowds comprising up to thousands of varied virtual humans navigating in large-scale, global environments.

Scalable Solutions for Simulating, Animating, and Rendering Real-Time Crowds of Diverse Virtual Humans

In this chapter, we describe how we can model crowds in real-time using dynamic meshes, static meshes and impostors.Techniques to introduce variety in crowds including colors, shapes, textures, individual animation, individualized path-planning, simple and complex accessories are explained. We also present a hybrid architecture to handle the path planning of thousands of pedestrians in real time, while ensuring dynamic collision avoidance. Several behavioral aspects are presented as gaze control, group behavior, as well as the specific technique of crowd patches. Several case-studies are shown in cultural heritage and social phobia.

Gaze Behaviors for Virtual Crowd Characters

Nowadays, crowds of virtual characters are used in many domains such as neurosciences, psychology, and computer sciences. Since as human beings, we are natural experts in human being representation and movement, it makes it that much harder to correctly model and animate virtual characters. This becomes even more challenging when considering crowds of virtual characters. Indeed, in addition to the representation and animation, there is the mandatory trade-off between rich, realistic behaviors and computational costs. In this paper, we present a crowd engine, to which we introduce and extra layer which allows its characters to produce gaze behaviors. We thus enhance crowd realism by allowing the characters composing it to be aware of their environment and other characters and/or a user.

EG 2006 Course on Populating Virtual Environments with Crowds

Crowds are part of our everyday experience; nevertheless, in virtual worlds they are still relatively rare. In the past, main reasons hindering a wider use of virtual crowds in the real-time domain were their high demands on both general and graphics performance coupled with high costs of content production. The situation is, though, changing fast; market forces are pushing performance of the consumer hardware up, reaching and surpassing performance of professional graphics workstations from just few years ago. With current consumer-grade personal computers it is possible to display 3D virtual scenes with thousands of animated individual entities at interactive framerates. In this report, we present the related works on the subject of groups and crowd simulation discussing several areas such as behavioral simulation, crowd motion control, crowd rendering and crowd scenario author-