(sourceId, properties, extract_voi.GetPointer());
elem->addActor(ActorIDs::Grid2D, actor);
auto id = m_visualElementCollector->addItem(elem);
elem->setId(id); // Store Visual element id
return { id, actor };
}
```
Thank you,
Carlo
---
### Author:  [@CharInt0](https://discourse.vtk.org/u/CharInt0)
#### Post date: [April 22, 2026, 1:42pm UTC](https://discourse.vtk.org/t/vtk-9-6-1-regression-in-edges-appearance/16393/2 "2026-04-22T13:42:51Z")
I have found the cause of the problem. The black edge is visible only if:
`auto* imageData = vtkImageData::SafeDownCast(gridData->getData());`
is created passing scalars that contain some values set to double.NAN. Otherwise it behaves as before without the black edges.
So it seems that it is not supported anymore or it is a regression in the new VTK .
Carlo
---
### Author:  [@sankhesh](https://discourse.vtk.org/u/sankhesh)
#### Post date: [April 23, 2026, 2:07pm UTC](https://discourse.vtk.org/t/vtk-9-6-1-regression-in-edges-appearance/16393/3 "2026-04-23T14:07:54Z")
The behavior of `vtkGeometryFilter` has changed in v9.6.1. Try toggling the `RemoveGhostInterfaces` i.e. in your code → `geo_filter->SetRemoveGhostInterfaces(false);`.
---
### Author:  [@CharInt0](https://discourse.vtk.org/u/CharInt0)
#### Post date: [April 23, 2026, 3:19pm UTC](https://discourse.vtk.org/t/vtk-9-6-1-regression-in-edges-appearance/16393/4 "2026-04-23T15:19:49Z")
Thank you Jhaveri
However I tried it but It seems not to work, either setting `SetRemoveGhostInterfaces(false) or SetRemoveGhostInterfaces(true)`.
In any case I’ve already changed my code and now I use a vtkUnsignedCharArray (I called it “ValidMask”) to keep a mask value for each NAN. I call a method that replace NAN to 0 and the pipeline code is filtering these values using the mask array and removing cells that are invalid (if any masked value is present):
```auto
auto* gridData = static_cast(sourceData.get());
auto* imageData = vtkImageData::SafeDownCast(gridData->getData()); // Do not get ownership
vtkNew extract_voi;
extract_voi->SetInputData(imageData);
extract_voi->SetSampleRate(properties.decimation, properties.decimation, 1);
extract_voi->UpdateWholeExtent();
vtkNew warp;
warp->SetInputConnection(extract_voi->GetOutputPort());
vtkNew geom;
geom->SetInputConnection(warp->GetOutputPort());
// Remove invalid geometry using the ValidMask array
vtkNew threshold;
threshold->SetInputConnection(geom->GetOutputPort());
threshold->SetInputArrayToProcess(0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_POINTS, "ValidMask");
threshold->SetUpperThreshold(0.5);
threshold->SetThresholdFunction(vtkThreshold::THRESHOLD_UPPER);
threshold->SetAllScalars(1); // do not keep cells where any of the point is invalid
// threshold -> unstructured grid -> back to polydata
vtkNew geom2;
geom2->SetInputConnection(threshold->GetOutputPort());
vtkNew triangle_filter;
triangle_filter->SetInputConnection(geom2->GetOutputPort());
vtkNew poly_data_norm;
poly_data_norm->SetInputConnection(triangle_filter->GetOutputPort());
vtkNew mapper;
mapper->SetInputConnection(poly_data_norm->GetOutputPort());
mapper->SetScalarRange(gridData->getZMin(), gridData->getZMax());
mapper->SetScalarModeToUsePointData();
auto actor = vtkSmartPointer::New();
actor->SetMapper(mapper);
actor->SetUserTransform(m_zTransform);
actor->GetProperty()->SetOpacity(properties.opacity);
actor->GetProperty()->SetLighting(properties.lighting);
```
It is working, although it may be not very optimized because I am duplicating the geometry (geom2).