Geopostors

Abstract

The simulation of large crowds of humans is important in many fields of computer graphics, including real-time applications such as games, as they can breathe life into otherwise static scenes and enhance believability. We present a novel hybrid rendering system for crowds that solves the classic problem of degraded quality of image-based representations at close distances by building an impostor rendering system on top of a full, geometry-based, human animation system. This enables almost imperceptible switching between the two representations based on a "pixel to texel" ratio, with minimal popping artefacts. Seamless interchanges are further facilitated by exploiting programmable graphics hardware to efficiently enhance the realism and variety of the dynamically-lit impostors, thereby also improving on existing impostor techniques. To test our system, our virtual crowds are embedded in an urban simulation system (as shown in Figure 1). The results demonstrate a system capable of rendering large realistic crowds with the visual realism of a high-resolution geometry rendering system, but at a fraction of the rendering cost.

Authoring Virtual Crowds: A Survey

“…The body‐parts identification and encoding process was performed using Autodesk 3DS Max. This technique has been widely accepted and employed for giving variety to crowds with few unique body meshes ([DHOO05], [MLD*08]). Similarly, De Heras et al [dHCSMT05] make a few grayscale base textures to create a variety of avatars differentiated by the colour of their clothing and accessories; this approach is based on alpha map channels encoding and deals with situations where triangles in the mesh template correspond to more than one region with different colours.…”

Gaze Behaviors for Virtual Crowd Characters

“…Impostors are 2D animated images, mapped onto a quad formed by 2 triangles. One pioneer work in this domain was achieved by Dobbyn et al [2]: they used pre-computed rigid meshes in front of the camera, and switched seamlessly to impostors for more distant characters. Later, Millan and Rudomin [3] presented a solution combining impostors and instanced geometries, maximizing the use of the GPU.…”

“…More recently, Kavan et al [4], presented a virtual human new level of detail, called polypostor : they are composed of a small set of 2D polygons, and animated by displacing their vertices. To avoid crowds of cloned entities, much work has been achieved on color variety, or how to modulate the colors of body parts for each instance of a same characters [5,2,6]. A recent study [7] has demonstrated that variety at the color level has much more impact on the user than varying the animations solely.…”

Populate Your Game Scene

“…Crowd Visualization is a specific problem with various solutions [1], [2], [3]. Briefly, these solutions rely on two major concepts.…”