//Get the variable profile whose renderer will be changed
var variable = voxelLayer.SelectedVariableProfile;
//Check DataType
if (variable.DataType != VoxelVariableDataType.Discrete)
return;//must be Discrete to have a UV Renderer...
var renderer = variable.Renderer as CIMVoxelUniqueValueRenderer;
//A CIMVoxelUniqueValueRenderer consists of a collection of
//CIMVoxelColorUniqueValue classes - one per discrete value
//in the associated variable profile value array
//Get the first class
var classes = renderer.Classes.ToList();
var unique_value_class = classes.First();
//Set its visibility off
unique_value_class.Visible = false;
//Apply the change to the renderer
renderer.Classes = classes.ToArray();
//apply the changes
variable.SetRenderer(renderer);