I am using AutoCAD MEP 2012 but have had the same issue with previous versions when plotting a 3D drawing that has 'hidden' shade viewports.I find that whilst the majority of lines are plotted either in a hard copy plot or pdf plot, there are consistently one or two lines that just will not print. Is this a common problem that people just accept? or is there some way to correct this. After spending days putting together a 3D drawing I find it frustrating that the end presentation plot is not perfect.Any ideas?

I use similar to MEP program based on AutoCAD and I have the same, sometimes helps changing rendered objects smootness to higher values. Chris 

The views saved in paperspace on my drawing are just 3D hidden line and not rendered.Thanks anyway Steve. Floyd

Did you try?

No, how do you do it?

you can change variable Facetres in command line or in options/display/rendered object smoothness, set maybe 4, but after plot change back to lower values because it slows down cad. 
kszyho2012-01-09 21:09:19

Wow! forgot all about this issue and don't tend to use blogs that often so apologies for missing your response way back in January!!Strange, but I haven't had this problem recently but will note your comments re rendered object smoothness if it crops up again.Thanks for taking the trouble to respond, much appreciated.