The Space Perception System with an unique three dimensional (3D) man-computer interface device was built for the experiments. An algorithm using distribution function was utilized to define model shapes in a virtual environment. In this, algorithm, the system was able to recognize the interference between the 3D cursor following an operator's hand and virtual objects in real-time. Impedance control of robotics was utilized to calculate a reaction force which was transmitted in real-time from the virtual object to the operator's hand through the 3D man-computer interface device. With the combination of the algorithm using distribution function and Impedance control, the operator could touch and trace on the virtual model which was composed of free-form surfaces in a virtual environment, and could recognize the hardness of it.