This .NET class wraps the AcDbPlotSettings ObjectARX class. 

The PlotSettings object stores "what-to-plot" settings as a named plot setup description. The plot settings objects are stored in an PlotSettingsDictionary.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.PlotSettings
        Autodesk.AutoCAD.DatabaseServices.Layout

Public Class PlotSettings
Inherits DBObject

public class PlotSettings : DBObject;

PlotSettingsValidator