diff --git a/js/importer.js b/js/importer.js
index a56e2e256d8a2592c3f87ddfb6c0e024242a0ade..94ac87a3ff4191367a9deb8a5b40a57b4b5b6b3c 100644
--- a/js/importer.js
+++ b/js/importer.js
@@ -191,6 +191,9 @@ function initImporter(globals){
                                     }
                                     creaseParams.push(foldSign*Math.PI);
                                     break;
+                                case "F":
+                                    creaseParams.push(0);
+                                    break;
                                 default:
                                     creaseParams.push(0);
                                     break;