Abstract
This paper deals with an approach to upper limbs therapy that uses virtual reality technologies. The previous methods and subsequent improvements of these procedures by means of a skeletal model of the upper limb in a virtual environment are presented here. So, main focus of the paper is on the description of calculation related to the bone rotation system within appropriate skeletal model. The therapist can add either more virtual upper limb objects or more virtual training objects to the virtual environment and thus expand/change the scene or the therapy complexity. The functions used in the limb movement calculations are useful for creating additional animations with various objects. With this system, the patient can be stimulated under the supervision of a therapist to practice certain rehabilitation procedures. Due to the use of collaborative web-based virtual reality, the therapy can be also applied in a remote form. The way in which the underlying idea of rehabilitation process is implemented and it is also described. In the conclusion are the some notes about system testing and evaluation including description of a therapist interface.