heyas; that's one of the mysteries of vue. vue can only do six levels of transparency. after that, it kicks in the 'murky' colour in the transparency of the material (usually that blue). when you create trees/plants and stack them, it doesn't seem to happen. but if you use the same plant leaf materials, it does. btw, they told me that vue 4 would do away with the 6 layer transparency limit. (i think.... who remembers what they said about that?)