fix _vtk import

Author: MariusCausemann

src/emimesh/extract_surfaces.py

@@ -9,7 +9,8 @@
 import shutil
 import itertools
 
-from pyvista.core import _vtk_core as _vtk
+from vtkmodules.vtkCommonDataModel import vtkPlaneCollection
+from vtkmodules.vtkFiltersGeneral import vtkClipClosedSurface
 from pyvista.core.filters import _get_output, _update_alg
 from pyvista.core.utilities.helpers import generate_plane
 
@@ -19,9 +20,9 @@
 def clip_closed_surface(surf, normal='x', origin=None, tolerance=1e-06, inplace=False, progress_bar=False):
 
     plane = generate_plane(normal, origin)
-    collection = _vtk.vtkPlaneCollection()
+    collection = vtkPlaneCollection()
     collection.AddItem(plane)
-    alg = _vtk.vtkClipClosedSurface()
+    alg = vtkClipClosedSurface()
     alg.SetGenerateFaces(True)
     alg.SetInputDataObject(surf)
     alg.SetTolerance(tolerance)