This .NET class wraps the AcDbRenderSettings ObjectARX class. 

This class is a container for all properties relating to a generic high-fidelity renderer. A dictionary of these objects is resident in the database, in the named object dictionary as ACAD_RENDER_SETTINGS. They are indexed by the name of the setting objects. In the user interface, the contents of this dictionary correspond to user-defined render presets (not predefined presets). 

The active render settings object is stored in the named object dictionary as ACAD_RENDER_ACTIVE_SETTINGS.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.RenderSettings
        Autodesk.AutoCAD.DatabaseServices.RapidRTRenderSettings

Public Class RenderSettings
Inherits DBObject

public class RenderSettings : DBObject;

MentalRayRenderSettings, RenderSettingsTraits