Recent progress in the material sciences has led to an increasing amount of interest in the role of textures for the behaviour of materials and in the mechanisms controlling the texture formation. This development was supported by a rather powerfull development taking place in the area of texture studies itself: Besides the usual, more qualitative, characterization of a texture by pole figures a fully quantitative description by a three-dimensional orientation distribution function (ODF) has been increasingly applied. There are two sides to the problem of quantitative representation of...