diff --git a/src/BambuStudio.cpp b/src/BambuStudio.cpp
index 1b0adfb3f..02847d50a 100644
--- a/src/BambuStudio.cpp
+++ b/src/BambuStudio.cpp
@@ -1337,7 +1337,7 @@ int CLI::run(int argc, char **argv)
         //"--filament-map",
         //"1,2,1,2",
         "--slice=0",
-        "cube_a1.3mf"
+        "stl_test.3mf"
         };
     if (! this->setup(debug_argc, debug_argv))*/
     if (!this->setup(argc, argv))
@@ -6848,8 +6848,8 @@ std::string CLI::output_filepath(const ModelObject &object, unsigned int index,
     // use --outputdir when available
     file_name = object.name.empty()?object.input_file:object.name;
     file_name = "obj_"+std::to_string(index)+"_"+file_name;
-    size_t pos = file_name.find_last_of(ext), ext_pos = file_name.size() - 1;
-    if (pos != ext_pos)
+    size_t pos = file_name.rfind(ext), ext_pos = file_name.size() - ext.size();
+    if ((pos == std::string::npos) || (pos != ext_pos))
         file_name += ext;
 
     BOOST_LOG_TRIVIAL(trace) << __FUNCTION__ << ": dir = "<< path_dir<<", file_name="<<file_name<< ", pos = "<<pos<<", ext_pos="<<ext_pos;