Mesh internal surface smoothing behavior changed in vtkWindowedSincPolyDataFilter - Support - VTK

It seems that the rewrite of vtkWindowedSincPolyDataFilter (that amazingly improved its performance) also changed how internal surfaces are smoothed. Smoothing of internal surfaces are important because when we segment a medical image we usually annotate many adjacent structures that have common surfaces and when we apply smoothing then we want to smooth surface of each structure and not just the outer surface of the entire segmented region. The old version (VTK8) smoothed the internal surfaces

Surface mesh with multiple scalar data - Support - 3D Slicer Community

PDF) The VTK User's Guide 11th Edition Contributors

attachment-0001.png

How to highlight a smooth region on a polygonal mesh - Support - VTK