In this paper, the authors present a physically based model for curtainreal-time animation, which not only significantly reduces the time of rendering, but also maintains visually appealing results. The curtain model is represented as an object composed of mass points connected by semi-rigid rods whose behavior is governed by non-rigid dynamics. The longitudinal (vertical) and latitudinal (horizontal) directions of the model are decoupled and processed separately, and later combined to generate the final curtain.