Translating Cartesian Coordinates from Hand frame to World Frame: ROS & Baxter Help

edit

So using tf echo i was able to obtain the position and rotation coordinates of the hand of my robot. but i can't seem to figure out how, using tf, i would transform coordinates from my hand to my base perspective

tf_echo is a nice command line tool, but what you really want to use is the tf library in your C++ or Python based node / script. Have you looked at the other tutorials?

yes i have, I actually figured out a way to get the transformation matrix using fromTranslationRotation()! Thank you so much!!

See if the tf2_ros::BufferInterface::transform(..) function already does what you want. Manually transforming poses is fine, but the utility functions exist for a reason.

Do yoiu know if there's an API for the BufferInterface for python? There this link(http://docs.ros.org/jade/api/tf2_ros/html/python/tf2_ros.html?highlight=bufferinterface) but somehow i can't access the buffer interface API

I think it's this but it appears the Python side is slightly under-documented. You might want to ask about that at the issue tracker.

I don't know much C++, But looking at the function in the c++ api, it says that it returns the transformed output. Which is a little confusing to me, since it doesn't know the input frame, only the frame you want to transform to

ROS msgs like geometry_msgs/Pose include a header.frame_id field. That contains what you call the input frame (or at least: it should contain it). Make sure you input properly setup Poses/Points/etc, and the rest should be taken care of for you.