Hi all, When I tried to create a 2-dim array with ROS's srv, I had some troubles with the server side. from file "srv/Joints.srv": float32[] joints from file "srv/ImportPC.srv": float32[] jts --- Joints[] trajectory In server.cpp, I tried to push_back a new Joints to trajectory like this: res.trajectory[0].joints.push_back(sum); It compiles, but of course at runtime it fails because trajectory[0] doesn't exist. So I tried something like this: import_pc::Joints_ Jts (); Jts.joints.push_back(sum); res.trajectory.push_back(Jts); However the template for import_pc::Joints_ is not correct. Any suggestion would be really appreciated. Thank you so much, Paul