Address vtk deprecation warning in vtkCellArray (#367)

Author: sadhana-r

src/openlifu/seg/skinseg.py

@@ -443,11 +443,10 @@ def _spherical_interpolator_from_mesh_embree(surface_mesh : vtk.vtkPolyData) ->
     vtk_points = surface_mesh.GetPoints()
     points_np = vtk_to_numpy(vtk_points.GetData()).astype(np.float64) # (N,3)
     polys = surface_mesh.GetPolys()
-    polys_np = vtk_to_numpy(polys.GetData()) # flat array [3,i0,i1,i2,3,i0,i1,i2,...]
-    if polys_np.size == 0:
+    connectivity_np = vtk_to_numpy(polys.GetConnectivityArray())
+    if connectivity_np.size == 0:
         raise RuntimeError("Input mesh has no polygons after transformation/triangulation.")
-    polys_np = polys_np.reshape(-1, 4) # (M, 4)
-    faces_np = polys_np[:, 1:4].astype(np.int64) # (M, 3)
+    faces_np = connectivity_np.reshape(-1, 3).astype(np.int64) # (M, 3)
 
     r_squared = np.sum(points_np**2, axis=1)
 

src/openlifu/virtual_fit.py

@@ -141,7 +141,7 @@ def __post_init__(self):
         if not isinstance(self.top_n_candidates, int ):
             raise TypeError("Number of transducer transform candidates returned must be an integer")
         if self.top_n_candidates <= 0:
-            raise TypeError("Number of transducer transform candidates returned must be greater than 0")
+            raise ValueError("Number of transducer transform candidates returned must be greater than 0")
 
     def to_units(self, target_units: str) -> VirtualFitOptions:
         """Do unit conversion and return a version of this VirtualFitOptions that uses