diff --git a/src/gpu/GridGenerator/io/STLReaderWriter/STLReader.cpp b/src/gpu/GridGenerator/io/STLReaderWriter/STLReader.cpp
index a1d0fbbd484d705f6f4f1d28a95e9c0e5ff42442..9c874456ff0956429fafb34cec9fff026a11cafb 100644
--- a/src/gpu/GridGenerator/io/STLReaderWriter/STLReader.cpp
+++ b/src/gpu/GridGenerator/io/STLReaderWriter/STLReader.cpp
@@ -86,7 +86,7 @@ std::vector<Triangle> STLReader::readASCIISTLWithPatches(const std::string& name
     std::ifstream file;
     file.open(name.c_str(), std::ifstream::in);
 
-    if( !file.is_open() ) throw std::runtime_error(name + "cannot be opened!");
+    if( !file.is_open() ) throw std::runtime_error(name + " cannot be opened!");
 
     uint currentPatchIndex = 0;