Simulating tendon motion with axial mass–spring system

Computer simulations provide an interactive platform for exploring the biomechanics of animal movement. Despite the substantial amount of work that has been devoted to simulate human models, simulation of human tendons and its effect on the deformation of skin layer has not been well addressed. In this paper, a graphical model is developed for simulating tendon motions with axial mass–spring system. Based on the deformation of tendons, the skin layer attached to the tendon is deformed accordingly.In the proposed model, the geometry of the tendon is defined by an axial curve. The appearance of the skin layer is determined based on the deformation of the underlying tendons. Given a human model in a motion, the axial curve is adjusted according to the relative position of the foot skeleton. The shape of the axial curve of the tendon that is used to control the deformation of the tendons is computed with a mass–spring system. In this article, simulation of human hand and foot models is demonstrated. A validation method is proposed to compare the tendon deformation between the simulated and the real data captured from the motion analysis system. Experimental results showed that the axial deformation technique can deform the hand and foot tendons with satisfactory accuracy in comparison with the real data. Besides, the models are simulated at an interactive frame rate. With the deformation of the tendons, the visual realism of human foot and hand simulation is enhanced.