Ask Your Question

Frame Conventions for Interactive Markers

asked 2014-07-16 19:45:23 -0500

David Lu gravatar image

You can attach Markers to the controls in InteractiveMarkers. The InteractiveMarker has its own Header/frame_id as does the Marker attached to the InteractiveMarkerControl.

If you publish two InteractiveMarkers that are completely identical except for the InteractiveMarker's frame_id, you get two different behaviors.

Let's say there's a moving frame called "up" and a stationary frame called "world." We want to put a marker at the up frame, so we create a simple box Marker with the frame_id "up". To make an interactive marker of this is easy, but you have the choice of whether to have the InteractiveMarker's frame_id be up or world.

If its up, then the marker will move with the frame up. However, if the IM's frame is "world", then the marker will NOT move with the frame.

This phenomenon is illustrated by this video and the following code.

Question: Is there some hidden semantics that I'm missing here, or is this just a bug?

#!/usr/bin/env python

import roslib; roslib.load_manifest("interactive_markers")
import rospy
from visualization_msgs.msg import *
from interactive_markers.interactive_marker_server import *
from tf import TransformBroadcaster
import tf.transformations

def make_marker(frame, color):
    int_marker = InteractiveMarker()
    int_marker.header.frame_id = frame = frame

    box_marker = Marker()
    box_marker.type = Marker.CUBE
    box_marker.scale.x = 0.5
    box_marker.scale.y = 0.05
    box_marker.scale.z = 0.05
    box_marker.color.r = color[0]
    box_marker.color.g = color[1]
    box_marker.color.b = color[2]
    box_marker.color.a = 1.0
    box_marker.header.frame_id = '/up'

    box_control = InteractiveMarkerControl()
    box_control.always_visible = True
    box_control.markers.append( box_marker )
    int_marker.controls.append( box_control )
    return int_marker

if __name__=="__main__":
    server = InteractiveMarkerServer("r2_teleop")

    server.insert(make_marker('/up', (0,0,1)))
    server.insert(make_marker('/world', (0,1,0)))

    tfx = TransformBroadcaster()
    start =
    while not rospy.is_shutdown():
        x = (
        yaw = (x % 10.0)*3.14*2/10.0
        tfx.sendTransform((0, 0, 0.5),
                     tf.transformations.quaternion_from_euler(0, 0, yaw),
edit retag flag offensive close merge delete


ROS has no bugs, only "undocumented features"!. LOL sorry for the useless comment, just had to say it :P Probably we just need to be careful to set the Marker frame_id and the InteractiveMarker frame_id to the same value. But don't take my word, I have no authority on the matter whatsoever

Martin Peris gravatar image Martin Peris  ( 2014-07-16 20:04:19 -0500 )edit

1 Answer

Sort by ยป oldest newest most voted

answered 2014-07-18 11:52:38 -0500

dgossow gravatar image

This is descibed in the InteractiveMarkerControl mesage definition:

# Markers to be displayed as custom visual representation.
# Leave this empty to use the default control handles.
# Note: 
# - The markers can be defined in an arbitrary coordinate frame,
#   but will be transformed into the local frame of the interactive marker.
# - If the header of a marker is empty, its pose will be interpreted as 
#   relative to the pose of the parent interactive marker.
Marker[] markers
edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2014-07-16 19:45:23 -0500

Seen: 493 times

Last updated: Jul 18 '14