diff --git a/assimp/Makefile b/assimp/Makefile
index da539e0..c3d6157 100644
--- a/assimp/Makefile
+++ b/assimp/Makefile
@@ -27,7 +27,7 @@ installed: $(SOURCE_DIR)/unpacked
 	touch installed
 
 clean:
-	-cd $(SVN_DIR)/build && make clean
+	-cd $(SOURCE_DIR)/build && make clean
 	-rm -f installed
 	-rm -rf include lib