A real-time method for manipulating a realistic human upper limb

Manipulation of the human upper limb in Computer Graphics is usually done using a kinematic chain representing the innermost elements, that is its main skeleton bones. When manipulated using the principles of direct or inverse kinematics, the chain can be used as a deformation tool for its external visible envelope, namely the skin. In this paper we present an innovative method to resolve the chain that will use both kinematics principles: inverse, to position the wrist; direct, to position the elbow and the shoulder. In order to propose a new approach for removing general stiffness and unrealistic movements of traditional solutions, some results from biomechanics were included in the model. This helped in recreating the scapulohumeral rhythm, as well as in limiting the movements of the human upper limb into its realistic workspace. In this way we were able to reproduce natural movements without additional efforts from the animator. Finally, we present advantages of the proposed method in terms of computational complexity when compared to traditional approaches. This will guarantee on desktop calculators a real-time interaction with the user for both single manipulation and crowd simulations.