diff --git a/chaudronnerie/CHO24.FCStd b/chaudronnerie/CHO24.FCStd
index 99becd3..5890c25 100644
Binary files a/chaudronnerie/CHO24.FCStd and b/chaudronnerie/CHO24.FCStd differ
diff --git a/tools/export-all-parts.py b/tools/export-all-parts.py
index 84e53f4..436b2fb 100644
--- a/tools/export-all-parts.py
+++ b/tools/export-all-parts.py
@@ -18,8 +18,10 @@ def convert_file(file_name, output_format):
 	root_objects = []
 	main_object = None
 	
+	#print("document: " + doc.Name)
 	for obj in doc.Objects:
 		if len(obj.Parents) == 0:
+			#print(obj.Label)
 			root_objects.append(obj)
 			if obj.Label == doc.Name:
 				main_object = obj
@@ -28,7 +30,7 @@ def convert_file(file_name, output_format):
 		main_object = root_objects[0]
 	
 	if main_object is None:
-		raise Exception("Can't find main object in file " + file_name)
+		raise Exception("Can't find main object in file " + file_name + " (found " + str(len(root_objects)) + " root object(s), none named like the document " + doc.Name + ")")
 		
 	secondary_objects = []
 	code_obj = doc.getObjectsByLabel('Code_Tube_Draft')
@@ -57,6 +59,10 @@ def convert_file(file_name, output_format):
 		os.makedirs(output_dir)
 	
 	Import.export([main_object], output_path)
+	
+	# close all documents
+	while len(FreeCAD.listDocuments().values()) > 0:
+		FreeCAD.closeDocument(list(FreeCAD.listDocuments().values())[0].Name)
 
 folders = [
 	'chaudronnerie',
@@ -66,6 +72,7 @@ folders = [
 for folder in folders:
 	files = os.listdir(project_folder + '/' + folder)
 	for source_file in files:
+		if not source_file.endswith('.FCStd'): continue
 		source_path = folder + '/' + source_file
 		print(source_path)
 		convert_file(source_path, 'step')