diff --git a/pandatool/src/eggprogs/eggTrans.cxx b/pandatool/src/eggprogs/eggTrans.cxx
index 273b069089..5fe652e607 100644
--- a/pandatool/src/eggprogs/eggTrans.cxx
+++ b/pandatool/src/eggprogs/eggTrans.cxx
@@ -70,7 +70,7 @@ run() {
 
   if (_triangulate_polygons) {
     nout << "Triangulating polygons.\n";
-    int num_produced = _data.triangulate_polygons();
+    int num_produced = _data.triangulate_polygons(true);
     nout << "  (" << num_produced << " triangles produced.)\n";
   }