This .NET class wraps the AcDbPlotSettings::ShadePlotResLevel ObjectARX class. 

This enumerated type defines the shade plot resolution level of the current PlotSettings object. The shade plot resolution level specifies the resolution at which shaded and rendered viewports will plot.

Public Enum ShadePlotResLevel
  Draft
  Preview
  Normal
  Presentation
  Maximum
  Custom
End Enum

public enum ShadePlotResLevel {
  Draft,
  Preview,
  Normal,
  Presentation,
  Maximum,
  Custom
}