public ExaggerationMode ExaggerationMode {get; set;}

{
  // Note: call within QueuedTask.Run()
  {
    //Offset
    var offset = voxelLayer.CartographicOffset;
    //apply an offset
    voxelLayer.SetCartographicOffset(offset + 100.0);

    //VerticalExaggeration
    var exaggeration = voxelLayer.VerticalExaggeration;
    //apply an exaggeration
    voxelLayer.SetVerticalExaggeration(exaggeration + 100.0);

    //Change the exaggeration mode to "ScaleZ" - corresponds to 'Z-coordinates' 
    //on the Layer properties UI - must use the CIM
    var def = voxelLayer.GetDefinition() as CIMVoxelLayer;
    def.Layer3DProperties.ExaggerationMode = ExaggerationMode.ScaleZ;
    //can set vertical exaggeration via the CIM also
    //def.Layer3DProperties.VerticalExaggeration = exaggeration + 100.0;

    //apply the change
    voxelLayer.SetDefinition(def);

    //Diffuse Lighting
    if (!voxelLayer.IsDiffuseLightingEnabled)
      voxelLayer.SetDiffuseLightingEnabled(true);
    var diffuse = voxelLayer.DiffuseLighting;
    //set Diffuse lighting to a value between 0 and 1
    voxelLayer.SetDiffuseLighting(0.5); //50%

    //Specular Lighting
    if (!voxelLayer.IsSpecularLightingEnabled)
      voxelLayer.SetSpecularLightingEnabled(true);
    var specular = voxelLayer.SpecularLighting;
    //set Diffuse lighting to a value between 0 and 1
    voxelLayer.SetSpecularLighting(0.5); //50%
  }
}