public class CIMTerrainDirtyAreaRenderer : CIMTinSimpleRenderer, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

{
  var dirtyAreaRendererDef = new TerrainDirtyAreaRendererDefinition();
  // accept default labels, symbolTemplate

  if (terrainLayer == null)
    return;
  // Note: Needs QueuedTask to run
  {
    if (terrainLayer.CanCreateRenderer(dirtyAreaRendererDef))
    {
      CIMTinRenderer renderer = terrainLayer.CreateRenderer(dirtyAreaRendererDef);
      if (terrainLayer.CanSetRenderer(renderer, SurfaceRendererTarget.DirtyArea))
        terrainLayer.SetRenderer(renderer, SurfaceRendererTarget.DirtyArea);
    }
  }
}