Lines fading out when plotting to a printer or to a PDF.

When I plot directly to a plotter or to a PDF file from paper space, some of the 3d pipe model will fade out along the pipe line. It happens to some of the lines, not all. I have re-drawn the pipes and drawn them using different UCS orientations. No change. I changed the layer color, changed the tessellation, line weight. Can this problem be related to the display driver, either software or video card? I have the latest drivers. ACAD ver. 11, nvidia quatro fx-3800 card.

Thanks

I am having the same issues. I wish I knew the solution. Maybe if you have better luck than I.