diff --git a/src/main.cc b/src/main.cc
index 5e2107b..3d30b6a 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -44,10 +44,10 @@ int main(int argc, char **argv) {
 	vtkNew<DihedralAnglesFilter> dihedralAnglesFilter;
 	dihedralAnglesFilter->SetInputConnection(tetMeshReader->GetOutputPort());
 
-	// vtkNew<vtkXMLPolyDataReader> polyMeshReader;
-	// polyMeshReader->SetFileName(argv[2]);
-	vtkNew<vtkOBJReader> polyMeshReader;
+	vtkNew<vtkXMLPolyDataReader> polyMeshReader;
 	polyMeshReader->SetFileName(argv[2]);
+	// vtkNew<vtkOBJReader> polyMeshReader;
+	// polyMeshReader->SetFileName(argv[2]);
 
 	vtkNew<RemoveExternalCellsFilter> removeExternalCellsFilter;
 	removeExternalCellsFilter->SetInputConnection(0,
diff --git a/src/remove_external_cells_filter.cc b/src/remove_external_cells_filter.cc
index f3a2455..55dafa2 100644
--- a/src/remove_external_cells_filter.cc
+++ b/src/remove_external_cells_filter.cc
@@ -1,6 +1,7 @@
 #include "remove_external_cells_filter.h"
 #include "point_tris_dist.h"
 
+#include <vtkCellType.h>
 #include <vtkUnstructuredGrid.h>
 #include <vtkDataObject.h>
 #include <vtkPolyData.h>
@@ -8,6 +9,7 @@
 #include <vtkCellData.h>
 #include <vtkCellIterator.h>
 #include <vtkSelectEnclosedPoints.h>
+#include <vtkUnsignedCharArray.h>
 
 
 vtkStandardNewMacro(RemoveExternalCellsFilter);
@@ -29,81 +31,6 @@ int RemoveExternalCellsFilter::FillInputPortInformation(
 }
 
 
-// static bool isSurfaceCell(vtkUnstructuredGrid *tetMesh, vtkIdType cellId) {
-// 	vtkNew<vtkIdList> facePoints;
-// 	vtkNew<vtkIdList> sharedCells;
-// 	for (vtkIdType faceId = 0; faceId < 4; faceId++) {
-// 		facePoints->InsertNextId((faceId + 0) % 4);
-// 		facePoints->InsertNextId((faceId + 1) % 4);
-// 		facePoints->InsertNextId((faceId + 2) % 4);
-// 		tetMesh->GetCellNeighbors(cellId, facePoints, sharedCells);
-// 		if (sharedCells->GetNumberOfIds() == 1) { // Surface cell.
-// 			return true;
-// 		}
-// 		facePoints->Reset();
-// 		sharedCells->Reset();
-// 	}
-// 	return false;
-// }
-
-
-// static void closestTri(vtkPolyData *polyMesh,
-// 					   vtkKdTree *kdTree,
-// 					   vtkStaticCellLinks *polyMeshLinks,
-// 					   double *point,
-// 					   double *closestTriDist,
-// 					   double *closestTriDirection) {
-// 	vtkIdType closestPoint;
-// 	{
-// 		double dummy;
-// 		closestPoint = kdTree->FindClosestPoint(point, dummy);
-// 	}
-// 	vtkIdType *triIds = polyMeshLinks->GetCells(closestPoint);
-// 	vtkIdType nTris = polyMeshLinks->GetNcells(closestPoint);
-
-// 	*closestTriDist = std::numeric_limits<double>::infinity();
-// 	for (vtkIdType j = 0; j < nTris; j++) {
-// 		vtkIdType cellId = triIds[j];
-// 		double direction[3];
-// 		double dist = pointTriangleDistance(point, polyMesh->GetCell(cellId),
-// 											direction);
-// 		if (dist < *closestTriDist) {
-// 			*closestTriDist = dist;
-// 			closestTriDirection[0] = direction[0];
-// 			closestTriDirection[1] = direction[1];
-// 			closestTriDirection[2] = direction[2];
-// 		}
-// 	}
-// }
-
-
-// static bool isExternalCell(vtkUnstructuredGrid *tetMesh,
-// 						   vtkPolyData *polyMesh,
-// 						   vtkStaticCellLinks *polyMeshLinks,
-// 						   vtkKdTree *kdTree,
-// 						   vtkIdType cellId) {
-// 	vtkNew<vtkIdList> pointIds;
-// 	tetMesh->GetCellPoints(cellId, pointIds);
-// 	double a[3], b[3], c[3];
-// 	tetMesh->GetPoint(pointIds->GetId(0), a);
-// 	tetMesh->GetPoint(pointIds->GetId(1), b);
-// 	tetMesh->GetPoint(pointIds->GetId(2), c);
-
-// 	double aDist, bDist, cDist;
-// 	double aDirection[3], bDirection[3], cDirection[3];
-// 	closestTri(polyMesh, kdTree, polyMeshLinks, a,
-// 			   &aDist, aDirection);
-// 	closestTri(polyMesh, kdTree, polyMeshLinks, b,
-// 			   &bDist, bDirection);
-// 	closestTri(polyMesh, kdTree, polyMeshLinks, c,
-// 			   &cDist, cDirection);
-// 	if (aDist > 0 && bDist > 0 && cDist > 0) {
-// 		return true;
-// 	}
-// 	return false;
-// }
-
-
 vtkTypeBool RemoveExternalCellsFilter::RequestData(
 	vtkInformation *request,
 	vtkInformationVector **inputVector,
@@ -112,43 +39,29 @@ vtkTypeBool RemoveExternalCellsFilter::RequestData(
 	vtkUnstructuredGrid* tetMesh = vtkUnstructuredGrid::GetData(inputVector[0]);
 	vtkPolyData *polyMesh = vtkPolyData::GetData(inputVector[1]);
 	vtkUnstructuredGrid* output = vtkUnstructuredGrid::GetData(outputVector);
-	// output->CopyStructure(tetMesh);
-	// output->GetPointData()->PassData(tetMesh->GetPointData());
-	// output->GetCellData()->PassData(tetMesh->GetCellData());
 
 	vtkNew<vtkSelectEnclosedPoints> selectEnclosedPoints;
 	selectEnclosedPoints->SetInputDataObject(0, tetMesh);
 	selectEnclosedPoints->SetInputDataObject(1, polyMesh);
 	selectEnclosedPoints->Update();
-	unsigned char *enclosedPoints = (unsigned char *)
-		selectEnclosedPoints->GetOutput()->GetPointData()
-		->GetArray("SelectedPoints")->GetVoidPointer(0);
-	vtkNew<vtkPoints> outPoints;
-	vtkNew<vtkIdList> outPointIds;
-	vtkIdType outPointId = 0;
-	outPointIds->SetNumberOfIds(4);
-	output->Allocate();
+	vtkUnsignedCharArray *enclosedPoints =
+		vtkUnsignedCharArray::SafeDownCast(
+			selectEnclosedPoints->GetOutput()
+			->GetPointData()->GetArray("SelectedPoints"));
+
+	vtkNew<vtkCellArray> outCells;
 	auto it = tetMesh->NewCellIterator();
-	for (it->InitTraversal();
-		 !it->IsDoneWithTraversal();
-		 it->GoToNextCell()) {
+	for (it->InitTraversal(); !it->IsDoneWithTraversal(); it->GoToNextCell()) {
 		vtkIdList *pointIds = it->GetPointIds();
-		if (!enclosedPoints[pointIds->GetId(0)]
-			&& !enclosedPoints[pointIds->GetId(1)]
-			&& !enclosedPoints[pointIds->GetId(2)]
-			&& !enclosedPoints[pointIds->GetId(3)]) {
-			outPointIds->SetId(0, outPointId + 0);
-			outPointIds->SetId(1, outPointId + 1);
-			outPointIds->SetId(2, outPointId + 2);
-			outPointIds->SetId(3, outPointId + 3);
-			outPointId += 4;
-			outPoints->InsertPoints(outPointIds, pointIds,
-									tetMesh->GetPoints());
-			output->InsertNextCell(it->GetCellType(), outPointIds);
+		if (enclosedPoints->GetValue(pointIds->GetId(0))
+		    || enclosedPoints->GetValue(pointIds->GetId(1))
+		    || enclosedPoints->GetValue(pointIds->GetId(2))
+		    || enclosedPoints->GetValue(pointIds->GetId(3))) {
+			outCells->InsertNextCell(it->GetPointIds());
 		}
 	}
-	outPoints->SetNumberOfPoints(outPointId + 3);
-	output->SetPoints(outPoints);
+	output->SetCells(VTK_TETRA, outCells);
+	output->SetPoints(tetMesh->GetPoints());
 
 	return true;
 }