We introduce a novel approach to capture linear and non linear motions of the skin surface due to muscle bugglings and other complex sub-surface interactions. Our method uses standard camera and consists of a video motion capture of the desired body surface covered by a stretchy and calibrated cloth. We develop a non model-based tracking method using regularity and topology of dedicated fabrics. Our tracking and 3D reconstruction methods support occlusions : we detect occlusions of 3D surfaces using temporal and spatial coherences, and are able to restart surface tracking once the occlusions have ended. The obtained 3D mesh can easily be integrated and adapted in a sequence of an animated virtual human. We demonstrate our method with the skinning of non-linear biceps deformations.