public class CIMVoxelStretchRenderer : CIMVoxelRenderer, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

{
  var variable = voxelLayer.GetVariableProfiles().First();
  var renderer = variable.Renderer;
  if (variable.DataType == VoxelVariableDataType.Continuous)
  {
    //Renderer will be stretch
    var stretchRenderer = renderer as CIMVoxelStretchRenderer;
    //access the renderer

  }
  else //VoxelVariableDataType.Discrete
  {
    //Renderer will be unique value
    var uvr = renderer as CIMVoxelUniqueValueRenderer;
    //access the renderer
  }
}