How to publish visualizat​ion_msgs/M​arker to ROS from MATLAB

Hello Community!

I am trying to publish visualization_msgs/Marker messages to ROS from MATLAB without luck. When i call rostopic echo in MATLAB i can see the data i am publishing , but in ROS i get the following:

WARNING: no messages received and simulated time is active. Is /clock being published?

(I am publishing on other topics as well from MATLAB, and those work well.) I have only problem with Marker messages.

Can someone give an example code/script of Marker publishing which worked and could visualize the data sent from MATLAB in rviz?

This is my code:

            obj.MarkerMsg.Header.FrameId = '/world';
            obj.MarkerMsg.Ns = 'points';
            obj.MarkerMsg.Header.Stamp = rostime('now','system');
            obj.MarkerMsg.Id = 0;
            obj.MarkerMsg.Scale.X = 0.03;
            obj.MarkerMsg.Scale.Y = 0.03;
            %obj.MarkerMsg.Scale.Z = 1;
                  
            tmppoints = [rosmessage('geometry_msgs/Point') rosmessage('geometry_msgs/Point')];
            tmppoints(1).X = 1.3;
            tmppoints(1).Y = 0;
            tmppoints(1).Z = 1.9;
            
            tmppoints(2).X = 1.3;
            tmppoints(2).Y = 0.3;
            tmppoints(2).Z = 1.9;
            
            obj.MarkerMsg.Points = tmppoints;
            
            Color = rosmessage('std_msgs/ColorRGBA');
            %Color.R = 1;
            Color.G = 1;
            %Color.B = 0;
            Color.A = 1;
            obj.MarkerMsg.Colors(1) = Color;
            obj.MarkerMsg.Colors(2) = Color;
            obj.MarkerMsg.Type = 8;
            
            send(obj.MarkerPub,obj.MarkerMsg);

Thank you in advance.

Best regards.

[Tohru Kikawada]

Which ROS distribution are you using?

Answer 1

[Chuhao Liu]

Hi

I meet similar question. That I use matlab try to read /visualization_msgs/InteractiveMarker, which is shows with error

[ERROR] [1544588729.446161141]: Client [/matlab_global_node_05131] wants topic /quad_marker to have datatype/md5sum [visualization_msgs/InteractiveMarkerUpdate/83e22f99d3b31fde725e0a338200e036], but our version has [visualization_msgs/InteractiveMarkerUpdate/710d308d0a9276d65945e92dd30b3946]. Dropping connection.

I think its message type in Matlab and ROS is different. But when I use Matlab send and read /visualization_msgs/Marker, it can receive the ros messages sent by matlab.

I have no idea how to solve this.

[Tohru Kikawada]

The following article may help you.

https://jp.mathworks.com/matlabcentral/answers/415195-robotics-system-toolbox-r2018a-ros-kinetic-visualization_msgs

The page is Japanese, so you'll need to translate into your language.