diff --git a/public/run_sax.js b/public/run_sax.js
index 6ee1b03c37628075f6bd862aabb33b98b7259739..ec26442663da514849fa2de4145b1777f1d943d6 100644
--- a/public/run_sax.js
+++ b/public/run_sax.js
@@ -553,6 +553,7 @@ input.addEventListener("change", function () {
     bbox = new BBox();
     setProgress(0);
     document.getElementById("progressDiv").style.removeProperty("display");
+    triangulatedPolygons = [];
     readSlice();
   }
 });