I am a bit embarrassed to ask this question, it is rather basic but it is important. What happens to hidden lines when a pdf is created for printing? Another way to pose the question is like this: say you have 3 solid discs of colour intersecting, each on a dedicated layer and in priority 1 over 2 over 3. for the purposes of neat accurate printing does it matter that the hidden lines disappear when the pdf is created? Or do they? Rather than have a hidden line/shape run under another, might it not be better for all visible shapes to abut each other even if in priority? I Ihope this makes sense. Thanku.