Recently force-feedback has been recognized to be important for virtual reality systems, and many studies have been done in this field. Although we have proposed several methods for displaying the operating feel of a virtual object by considering its dynamics, we have not dealt with cases of multiple objects or operators. In more advanced applications of haptic virtual reality, however, multiple operators and multiple objects will generally exist in the virtual world. In this paper, we propose a systematic method of constructing a virtual world by combining the dynamics modules and interaction modules, the former denoting elements of the virtual world (virtual objects or operators) and the latter denoting interactions between them. Since this method makes it possible to regard those elements as equal, we can construct a flexible and extendable virtual world to which we can easily add new elements or remove some of its elements. An experimental result using a prototype force display system shows the validity of the proposed method.