diff --git a/VirtualRobot/Obstacle.cpp b/VirtualRobot/Obstacle.cpp
index 78230c03c9ae5da00cfd729aa9b492cf19936af9..27baf65350b5d248d45a209bc18f7b9b9c4c5ceb 100644
--- a/VirtualRobot/Obstacle.cpp
+++ b/VirtualRobot/Obstacle.cpp
@@ -328,7 +328,7 @@ namespace VirtualRobot
     }
 
 
-    std::string Obstacle::getFilename()
+    std::string Obstacle::getFilename() const
     {
         return filename;
     }
diff --git a/VirtualRobot/Obstacle.h b/VirtualRobot/Obstacle.h
index 82257a2d814e00a481419bf0bc4db22c3f48b771..59554e1007aa064f6dd160bd21468f044b1251e2 100644
--- a/VirtualRobot/Obstacle.h
+++ b/VirtualRobot/Obstacle.h
@@ -113,7 +113,7 @@ namespace VirtualRobot
         virtual std::string toXML(const std::string& basePath, int tabs = 0);
 
         void setFilename(const std::string& filename);
-        std::string getFilename();
+        std::string getFilename() const;
 
     protected: