We have developed a method for applying 3D virtual humans in a computer generated virtual city, and for managing all objects which form an entire virtual space. In this paper we offer a way of combining natural human movements with virtual human characters, and we propose concrete methods for controlling various objects such as virtual humans, cars or buildings by using an index-based database system. For implementing our proposed method, we constructed web-based interfaces, which eive creators/users the possibility to construct/experience the contents. As an application case of our created system, we introduce a dramatization method of virtual humans in a near future city.