Thanks a million, Thomas. I am yet another user who had not discovered the material distribution map feature! Its power and flexibility is immediately obvious, particularly when a quick experiment shows how it can be used in combination with all the other features such as height/slope dependency etc. and that you can use full-coloured pictures as maps as well (Vue automatically extracting the grey-scale information from these when used as a material map). This is going to make numerous effects possible that I previously would have added in post.