Rendering and animating a multitude of articulated characters in real-time presents a real challenge, and few hardware systems are up to the task. Up to now, little research has been conducted to tackle the issue of real-time rendering of numerous virtual humans. However, due to the growing interest in collaborative virtual environments, the demand for numerous realistic avatars is becoming stronger. This paper presents a hardware-independent technique that improves the display rate of animated characters by acting on the geometric and rendering information. We first review the acceleration techniques traditionally used in computer graphics and highlight their suitability for articulated characters. Then we show how impostors can be used to render virtual humans. Finally, we introduce a concrete case study that demonstrates the effectiveness of our approach