A Training System for the Japanese Art of Flower Arrangement

Computer Graphics (CG) and Virtual Reality (VR) technologies have rapidly improved in recent years. It enabled us to develop some useful systems such as air hockey, catch ball, tennis and horseback riding for sports field, surgical simulations and support systems for medical field, calligraphy and flower arrangement for educational field. The good training systems have force feedback for users to feel so that they can learn the skills effectively. These days, there are so many systems that use CG and VR technologies; however, there are little training systems for the Japanese art of flower arrangement. One system is a robot that can make an arranged flower according to the training data, and others are learning systems, with which people can train for flower arrangement. These systems, however, are two dimensional and do not have force feedback. Although they can learn the beauty of flower arrangement, they cannot learn the feeling when they insert flowers into pinholders. Therefore, we have developed a training system for the Japanese art of flower arrangement, which is a three dimensional system so that people can see the arranged flowers from any viewpoint. Users can also feel the tactile sense when they insert flowers into pinholders and also when flowers, which users are having, contact with other flowers. In order to make the tactile sense of flower arrangement, this system has a haptic device that can generate force feedback. By measuring the hardness of flowers with a durometer and applying the measurement results to the system, we can generate real force feedback. In order to perform fast collision detection between a flower and a pinholder or among flowers, the flower model is hierarchically constructed with some parts such as petal, stem and leaf. Each part also has one of three attributes that are “Active”, “Inactive” and “Passive” so that fast and effective collision detection can be performed. For the real force feedback, the hardnesss of some flower stems is measured with a durometer, and the flowers are sorted into three types: soft grass, hard grass and branch. An approximated equation, which calculates the force according to the flower type, is introduced based on the result of the mesurement. The measured datum, however, is a force that is generated when the stem of a flower contacts with one pin of a pinholder. Then the number of pins that contact with the stem should be calculated according to the radius of the stem, and the true force should be calculated by multiplying the measured force with the number of pins. Finally, the training system is consructed with a personal computer (PC) and a haptic device (see Fig. 1 (a)). By using the stick of the haptic device, users can grab a flower and insert it into a pinholder. They can feel the force feedback during inserting it into the pinholder and when the flower contacts with another one. Unless the flower is deeply enough inserted into the pinholder, the flower falls down so that the falling down simulation is necessary. The simulation image appears on the display of the PC (see Fig. 1 (b)). They can not only change the viewpoint but also make zooming in and out of the image at any time. As the result of some questionnaires to users, they can feel the force feedback and can train for the skill of flower arrangement by themselves without any real flowers.