allowing newer vtk-mesh-formats fix

ntrfc/utils/filehandling/mesh.py

@@ -6,8 +6,11 @@ import pyvista as pv
 def load_mesh(path_to_mesh):
     assert os.path.isfile(path_to_mesh), path_to_mesh + " is not a valid file"
     extension = os.path.splitext(path_to_mesh)[1]
-    if extension == ".vtk" or extension == ".vtp" or extension == ".vtu" or extension == ".vtm":
+    if extension == ".vtk" or extension == ".vtp" or extension == ".vtu" :
         mesh = pv.read(path_to_mesh)
+    elif  extension == ".vtm":
+        multiBlockMesh = pv.read(cgns)
+        mesh = multiBlockMesh.combine()
     elif extension == ".cgns":
         cgns = cgnsReader(path_to_mesh)
         if str(type(cgns)).find('vtkStructuredGrid') != -1: