D. Baraff and A. Witkin. Large Steps in Cloth Simulation. Computer Graphics Proceedings, Annual Conference Series: 43-54, 1998 Adobe Acrobat (PDF) (12 pages, 255K). D. Baraff. Linear-time dynamics ...

This paper presents a method for constructing smooth unit n-direction fields (line fields, cross fields, etc.) on surfaces that is an order of magnitude faster than state-of-the-art methods, while ...

Do not be daunted by the many options of the function make-array. All that is required to construct an array is a list of the dimensions; most of the options are for relatively esoteric applications.