public Nullable<double> Value {get; set;}

{
  // Note: call within QueuedTask.Run()
  {
    //Visualization must be surface
    if (voxelLayer.Visualization != VoxelVisualization.Surface)
      voxelLayer.SetVisualization(VoxelVisualization.Surface);

    //Get the variable profile on which to create the iso surface
    var variable = voxelLayer.SelectedVariableProfile;

    // o Visualization must be Surface
    // o Variable profile must be continuous
    // o Variable MaxNumberofIsoSurfaces must not have been reached...
    if (variable.CanCreateIsosurface)
    {
      //Note: calling create if variable.CanCreateIsosurface == false
      //will trigger an InvalidOperationException

      //Specify a voxel value for the iso surface

      var min = variable.Statistics.MinimumValue;
      var max = variable.Statistics.MaximumValue;
      var mid = (max + min) / 2;

      //color range (i.e. values that are being rendered)
      var renderer = variable.Renderer as CIMVoxelStretchRenderer;
      var color_min = renderer.ColorRangeMin;
      var color_max = renderer.ColorRangeMax;

      //keep the surface within the current color range (or it
      //won't render)
      if (mid < color_min)
      {
        mid = renderer.ColorRangeMin;
      }
      else if (mid > color_max)
      {
        mid = renderer.ColorRangeMax;
      }

      //Create the iso surface
      var suffix = Math.Truncate(mid * 100) / 100;
      variable.CreateIsosurface(new IsosurfaceDefinition()
      {
        Name = $"Surface {suffix}",
        Value = mid,
        IsVisible = true
      });
    }
  }
}

{
  // Note: call within QueuedTask.Run()
  {
    var variable = voxelLayer.SelectedVariableProfile;

    //Change the color of the first surface for the given profile
    var surface = variable.GetIsosurfaces().FirstOrDefault();
    if (surface != null)
    {
      if (voxelLayer.Visualization != VoxelVisualization.Surface)
        voxelLayer.SetVisualization(VoxelVisualization.Surface);

      //Change the iso surface voxel value
      surface.Value = surface.Value * 0.9;

      //get a random color
      var count = new Random().Next(0, 100);
      var colors = ColorFactory.Instance.GenerateColorsFromColorRamp(
        ((CIMVoxelStretchRenderer)variable.Renderer).ColorRamp, count);

      var idx = new Random().Next(0, count - 1);
      surface.Color = colors[idx];
      //set the custom color flag true to lock the color
      //locking the color prevents it from being changed if the
      //renderer color range or color theme is updated
      surface.IsCustomColor = true;

      //update the surface
      variable.UpdateIsosurface(surface);
    }
  }
}