I just tried the vmtk extension on mac with Slicer 4.8 and confirmed it isn’t working.
There’s an issue with the python library:
>>> import vtkvmtkSegmentationPython as vtkvmtkSegmentation
Traceback (most recent call last):
File "<console>", line 1, in <module>
ImportError: dlopen(/Applications/Slicer-4.8.0.app/Contents/Extensions-26489/SlicerVMTK/lib/Slicer-4.8/qt-loadable-modules/Python/vtkvmtkSegmentationPython.so, 2): Library not loaded: libvtkvmtkSegmentationPythonD.dylib
Referenced from: /Applications/Slicer-4.8.0.app/Contents/Extensions-26489/SlicerVMTK/lib/Slicer-4.8/qt-loadable-modules/Python/vtkvmtkSegmentationPython.so
Reason: image not found