A method, and apparatus, and a computer-readable medium encoded with instructions to carry out a method. The method is of rendering a model of a surface of wrinkly material such as paper or foil, e.g., a model of packaging on a display device. The method includes accepting a description of the different parts of the surface of the packaging, and how and where any of the parts are connected, discretizing to form a mesh, modelling the physics of the mesh, running a simulation to find a stable end-state for the mesh, modifying the mesh to visually smooth the mesh in a way that is perceived as typical for flexible packaging material; and rendering the model on a display device. The modifying the mesh is to visually smooth the mesh includes modifying during the rendering or modifying prior to the rendering.