Lines Merge

What's wrong with this picture? These two AutoCAD plots were made with all the same settings: Plotter, pen table, scale, etc. from the same drawing/same layers. However, the first image displays the lighting fixtures as bold and readable, whereas the second image shows the lights as obscured by the ceiling grid.
The only difference between the first and second plot is the order the entities were drawn in the database. In image two, the ceiling grid was placed last (or xreferenced last) and so is on top of the underlying light fixtures.

Can this be controlled? Can we force the light fixtures to show bold? The answer is a qualified yes.

For most plotters the default setting for Merge Control is Lines Overwrite. This means that the last entity placed in the database is plotted on top of other entities. At Benham, we typically change this setting on all of our plot devices to Lines Merge.This allows the bold, solid black light fixtures to "show through" the screened, gray ceiling grid.

Now for the qualification: not all plotter drivers have the Lines Merge ability; the DWG to PDF.pc3 for example does not. So now how does one make sure that the light fixtures plot bold and black when plotting to PDF? You're going to need to ensure that they're on top. Use the DRAWORDER command to send the ceiling grid to the back or bring the lights to the top.