diff --git a/src/main.cc b/src/main.cc
index baaaa5e..eccb986 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -61,21 +61,39 @@ vtkAlgorithm *readerFromFileName(const char *fileName) {
 }
 
 
+static void usage(char **argv) {
+	std::cerr << "Usage: " << argv[0] << " analyze|fit tetmesh polydata [radiusScale relaxationIterCount]" << std::endl;
+}
+
+
 int main(int argc, char **argv) {
-	if (!(argc == 3 || argc == 5)) {
-		std::cerr << "Usage: " << argv[0] << " tetmesh polydata [radiusScale relaxationIterCount]" << std::endl;
+	if (argc < 4) {
+		usage(argv);
+		return EXIT_FAILURE;
+	}
+	bool fit = false;
+	if (std::string(argv[1]) == "fit") {
+		fit = true;
+	} else if (std::string(argv[1]) != "analyze") {
+		usage(argv);
+		return EXIT_FAILURE;
+	}
+	if ((fit && argc > 6) || (!fit && argc != 4)) {
+		usage(argv);
 		return EXIT_FAILURE;
 	}
 
 	double radiusScale = 2.;
 	int iterCount = 1;
-	if(argc > 3) {
+	if(argc > 4) {
 		radiusScale = std::stod(argv[3]);
+	}
+	if (argc > 5) {
 		iterCount = std::stoi(argv[4]);
 	}
 
-	auto tetMeshReader = readerFromFileName(argv[1]);
-	auto polyMeshReader = readerFromFileName(argv[2]);
+	auto tetMeshReader = readerFromFileName(argv[2]);
+	auto polyMeshReader = readerFromFileName(argv[3]);
 
 	vtkNew<RemoveExternalCellsFilter> removeExternalCellsFilter;
 	removeExternalCellsFilter->SetInputConnection(0,
@@ -97,8 +115,13 @@ int main(int argc, char **argv) {
 	relaxationFilter->SetInputConnection(project->GetOutputPort());
 
 	vtkNew<DihedralAnglesFilter> dihedralAnglesFilter;
-	dihedralAnglesFilter->SetInputConnection(
-		relaxationFilter->GetOutputPort());
+	if (fit) {
+		dihedralAnglesFilter->SetInputConnection(
+			relaxationFilter->GetOutputPort());
+	} else {
+		dihedralAnglesFilter->SetInputConnection(
+			tetMeshReader->GetOutputPort());
+	}
 
 	vtkNew<vtkGeometryFilter> geometryFilter;
 	geometryFilter->SetInputConnection(dihedralAnglesFilter->GetOutputPort());
@@ -107,11 +130,15 @@ int main(int argc, char **argv) {
 	maxDistanceFilter->SetInputConnection(0, geometryFilter->GetOutputPort());
 	maxDistanceFilter->SetInputConnection(1, polyMeshReader->GetOutputPort());
 
-	vtkNew<vtkXMLUnstructuredGridWriter> writer;
-	writer->SetInputConnection(dihedralAnglesFilter->GetOutputPort());
-	writer->SetDataModeToAscii();
-	writer->SetFileName("out.vtu");
-	writer->Write();
+	if (fit) {
+		vtkNew<vtkXMLUnstructuredGridWriter> writer;
+		writer->SetInputConnection(dihedralAnglesFilter->GetOutputPort());
+		writer->SetDataModeToAscii();
+		writer->SetFileName("out.vtu");
+		writer->Write();
+	} else {
+		dihedralAnglesFilter->Update();
+	}
 
 	maxDistanceFilter->Update();
 	std::cerr << "Max distance: " << maxDistanceFilter->GetMaxDist() << "\n"