How to label model according to cell data?

VR/AR
,
1

I have model (*.vtu) containing several blocks like:

Untitled
Untitled1054×641 35.8 KB

I want to label values on each block like:
labels

How can I do it ? I can access values using:

vtkActor actor = ...;
var output = actor.GetMapper().GetInputAsDataSet();
var cell = output.GetCellData();
for (int i = 0; i < cell.GetNumberOfComponents(); i++)
{
    var cells = cell.GetArray(i);
    if (cells == null) continue;
    if ("IJK" != cell.GetArrayName(i)) continue; //There are many columns. I used IJK column as testing purpose
    var min = cells.GetRange()[0];
    var max = cells.GetRange()[1];
    for (int j = 0; j < nCells; j++)
    {
        double val = cells.GetComponent(j, i);
        // how to label this value now ?
    }
    break;
}         
vtkDataSetMapper mapper = vtkDataSetMapper.New();
mapper.SetInput(output);
actor.SetMapper(mapper);

Here’s attached my model file: model.zip (3.1 MB)