diff --git a/extras/CMakeLists.txt b/extras/CMakeLists.txt
index 5944b0a96..726d02e78 100644
--- a/extras/CMakeLists.txt
+++ b/extras/CMakeLists.txt
@@ -24,6 +24,13 @@ target_link_libraries(largeSceneTest manifold)
 target_compile_options(largeSceneTest PRIVATE ${MANIFOLD_FLAGS})
 target_compile_features(largeSceneTest PUBLIC cxx_std_17)
 
+if(MANIFOLD_EXPORT)
+  add_executable(convertFile convert_file.cpp)
+  target_link_libraries(convertFile manifold meshIO)
+  target_compile_options(convertFile PRIVATE ${MANIFOLD_FLAGS})
+  target_compile_features(convertFile PUBLIC cxx_std_17)
+endif()
+
 if(BUILD_TEST_CGAL)
     add_executable(perfTestCGAL perf_test_cgal.cpp)
     find_package(CGAL REQUIRED COMPONENTS Core)
diff --git a/extras/convert_file.cpp b/extras/convert_file.cpp
new file mode 100644
index 000000000..b9e7ca0e7
--- /dev/null
+++ b/extras/convert_file.cpp
@@ -0,0 +1,67 @@
+// Copyright 2023 The Manifold Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <iostream>
+
+#include "manifold.h"
+#include "meshIO.h"
+
+using namespace manifold;
+
+/*
+ */
+int main(int argc, char** argv) {
+  if (argc < 2) {
+    std::cout << "Specify an input filename." << std::endl;
+    return 1;
+  }
+
+  manifold::ManifoldParams().verbose = true;
+
+  const std::string filename(argv[1]);
+
+  MeshGL input = ImportMesh(filename);
+  std::cout << input.NumVert() << " vertices, " << input.NumTri()
+            << " triangles" << std::endl;
+
+  if (input.Merge())
+    std::cout << filename << " is not manifold, attempting to fix."
+              << std::endl;
+
+  const Manifold manifold(input);
+  if (manifold.Status() != Manifold::Error::NoError) {
+    std::cout << "Could not make a valid manifold, error: "
+              << (int)manifold.Status() << std::endl;
+    return 2;
+  }
+
+  const std::vector<Manifold> parts = manifold.Decompose();
+  std::cout << parts.size() << " objects:" << std::endl;
+  for (const Manifold& part : parts) {
+    auto prop = part.GetProperties();
+    std::cout << part.NumVert() << " vertices, " << part.NumTri()
+              << " triangles, volume = " << prop.volume
+              << ", surface area = " << prop.surfaceArea << std::endl;
+  }
+
+  if (argc == 3) {
+    std::string outName = argv[2];
+
+    std::cout << "Writing " << outName << std::endl;
+
+    ExportMesh(outName, manifold.GetMeshGL(), {});
+  }
+
+  return 0;
+}
\ No newline at end of file
diff --git a/meshIO/include/meshIO.h b/meshIO/include/meshIO.h
index e7a7ddef6..c11309949 100644
--- a/meshIO/include/meshIO.h
+++ b/meshIO/include/meshIO.h
@@ -19,10 +19,6 @@
 
 namespace manifold {
 
-/** @addtogroup Debug
- *  @{
- */
-
 /** @defgroup MeshIO
  *  @brief 3D model file I/O based on Assimp
  * @{
@@ -70,5 +66,4 @@ void ExportMesh(const std::string& filename, const Mesh& mesh,
 void ExportMesh(const std::string& filename, const MeshGL& mesh,
                 const ExportOptions& options);
 /** @} */
-/** @} */
 }  // namespace manifold
\ No newline at end of file
diff --git a/src/manifold/src/edge_op.cpp b/src/manifold/src/edge_op.cpp
index 222c53a3d..c7378e3a7 100644
--- a/src/manifold/src/edge_op.cpp
+++ b/src/manifold/src/edge_op.cpp
@@ -152,6 +152,13 @@ void Manifold::Impl::SimplifyTopology() {
       flaggedEdges.begin();
   flaggedEdges.resize(numFlagged);
 
+#ifdef MANIFOLD_DEBUG
+  if (ManifoldParams().verbose && numFlagged > 0) {
+    std::cout << "found " << numFlagged << " duplicate edges to split"
+              << std::endl;
+  }
+#endif
+
   for (const int edge : flaggedEdges) DedupeEdge(edge);
 
   flaggedEdges.resize(halfedge_.size());
@@ -162,6 +169,13 @@ void Manifold::Impl::SimplifyTopology() {
       flaggedEdges.begin();
   flaggedEdges.resize(numFlagged);
 
+#ifdef MANIFOLD_DEBUG
+  if (ManifoldParams().verbose && numFlagged > 0) {
+    std::cout << "found " << numFlagged << " short edges to collapse"
+              << std::endl;
+  }
+#endif
+
   for (const int edge : flaggedEdges) CollapseEdge(edge);
 
   flaggedEdges.resize(halfedge_.size());
@@ -172,6 +186,13 @@ void Manifold::Impl::SimplifyTopology() {
       flaggedEdges.begin();
   flaggedEdges.resize(numFlagged);
 
+#ifdef MANIFOLD_DEBUG
+  if (ManifoldParams().verbose && numFlagged > 0) {
+    std::cout << "found " << numFlagged << " colinear edges to collapse"
+              << std::endl;
+  }
+#endif
+
   for (const int edge : flaggedEdges) CollapseEdge(edge);
 
   flaggedEdges.resize(halfedge_.size());
@@ -183,6 +204,12 @@ void Manifold::Impl::SimplifyTopology() {
       flaggedEdges.begin();
   flaggedEdges.resize(numFlagged);
 
+#ifdef MANIFOLD_DEBUG
+  if (ManifoldParams().verbose && numFlagged > 0) {
+    std::cout << "found " << numFlagged << " edges to swap" << std::endl;
+  }
+#endif
+
   for (const int edge : flaggedEdges) {
     RecursiveEdgeSwap(edge);
   }