diff --git a/.gitignore b/.gitignore
index 974af6d..f209ca6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,7 @@
 # ---> C++
 # Prerequisites
 *.d
-
+*.sdf
 # Compiled Object files
 *.slo
 *.lo
diff --git a/HEZON_ITK/bs_sign_cad.cpp b/HEZON_ITK/bs_sign_cad.cpp
index afc7fe1..2e9dbb9 100644
--- a/HEZON_ITK/bs_sign_cad.cpp
+++ b/HEZON_ITK/bs_sign_cad.cpp
@@ -69,6 +69,9 @@ int bs_sign_cad(EPM_action_message_t msg)
 				if(ref)
 				{
 					IMF_ask_original_file_name2(ref, &name);
+					string temp = name;
+					if (temp.find(".dwg") == -1)
+						continue;
 					stringstream path;
 					path << tempdir <<"\\"<< newGUID() << name;
 					printf("path:%s\n", path.str().c_str());