Level of detail for complex urban scenes with varied animated crowds, using XML

We present a system capable of handling several thousands of varied animated characters within a crowd. These characters are designed to have geometric, color animation and behaviour variety, nevertheless when a crowd becomes bigger, more memory is needed and is often difficult to achieve this objective. To solve this problem, we implemented two complementary data structures

Real-time clothing: geometry and physics

This paper describes a technique that allows pieces of clothing to be placed over an animated articulated character in real-time. In order to do this, the character to be dressed must be approximated using a hierarchy of ellipsoids. The pieces of clothing are represented using mass-spring particle systems; the particles move by applying dynamic forces to them and integrating the system with an explicit method. Penetration of the character’s ellipsoids by any particle are avoided; to facilitate and accelerate these calculations the ellipsoids are arranged in groups and an adjacency graph is constructed between these groups. This method is fast enough to deliver real-time performance on mid-range PCs and workstations, using only portable and standard C++ and OpenGL code

Embodied modelling tools in a 3D environment

Most 3D modelling tools available today operate using interfaces based on traditional static menus, which implies that the user must go through a long training period before he can use the modelling tool in a productive manner. In this paper we explore the definition and use of new embodied modelling tools within a 3D environment. Each embodied tool works in its own virtual 2D space that senses the action and movements of the “mouse” and translates them into operations over the elements of a 3D scene. We develop embodied modelling tools covering the most common operations of a traditional modelling program, including creating, colouring, lighting and editing objects, as well as showing the internal hierarchy of the scene. Lastly, we conclude by describing the characteristics of the modelling tools that have been shown to be useful in improving interaction

Multi-Layer Implicit Garment Models

This paper presents a new way to model clothing worn by articulated implicit characters. A scalar field is produced using ellipsoids as primitives. Isosurfaces are then used to place garments in one or more layers. As each implicit surface is independent, collision detection is not needed. The cloth is a polygonal mesh whose vertices are in turn moved towards their destination isosurface using the gradient of the scalar field. In order to maintain the cloth's shape and size a net of simple springs is used. We improve appearance by adding noise to simulate wrinkles and light wind. 1. Introduction Computer animations that we can see today consist mostly of rigid solid objects. Lately, however, we are starting to see flexible objects being used more often. Solid objects are usually described by a polygon mesh that is too complex to manage in a vertex by vertex way, as is often the case when dealing with flexible characters. Implicit surfaces can be used to model them. An implicit surfa..