I could use mapped textures, but using the procedural textures is kind of an experiment if I can get the same results with procedural textures that is possible with mapped pictures. Actually it is quite possible to get even better results, but you have to add a lot of complicated functions with multiple layers of noise to get any usable result. What seems strange to me is, that the preview is slow while all other functions using the texture (the little picture-preview, the zoom-function) are quite fast. Only the little preview in the texture editor is slow. Joerg