Objects are there in Plot Preview but are missing from final output

[jonathan_fairholm]

The drawings I work on are larger factory /site layouts. In some cases, it is necessary for me to show the surrounding geographical features, such as dwellings and urban features.
These features are obtained from Ordnance Survey and are inserted as an XREF around our site boundary. I have been using this method for some time with no problem. But recently, when I wish to plot one of these drawings, the XREF appears fine in the print preview, but doesn't appear on the paper copy - all I get is my site (no surroundings).
I have checked things like the XREF layer is not frozen and is not set to 'do not plot' and is not set on vp freeze etc. This has also happened with other drawings that don't contain XREFS - where a particular layer is visible in the plot preview, but doesn't come out on the paper. The only way have have managed to overcome this problem is to paste everything into a new drawing and drop in all the layouts using design center, then overwrite the original drawing. I haven't a clue how to overcome this problem properly.

[jonathan_fairholm]

During my investigations, I have found that if background plotting is disabled the problem disappears completely. This However is not a solution. I find that standard plot spooling uses far to much RAM to process the plot and causes my system to crash. I already have 1.5GB of RAM. If background plotting is disabled then I can only plot a drawing if no other drawings are open at that time. Therefore, I find background plotting an essential feature.
So why does background plotting produce different results to standard plotting??

[Mike.Perry]

Hi

With BackGroundPlot enabled a second session of AutoCAD is being run. The below snippets are taken from an AutoCAD 2005 review on JTB World -

<snip>
Background plotting is added. You can choose if you want single and/or multiple plots with Publish being plotted in the background or not. The reason is that AutoCAD opens a new instance of AutoCAD that makes the plot and that takes of course a little time and memory.
</snip>

Have a good one, Mike