Eohan, > I want to use tf transforms(_geometry_msgs__TransformStamped) to find the > transformation(trans) between two transformations(say tf1 and tf2). > Basically, > tf1 = trans*tf2 > Is this possible to do in python without explicitly publishing the tf1 and > tf2 and subscribing to the trans? Seems like its a trivial function that > should exist. Tf is not designed to be a library for geometric operations. Instead you can use a library like PyKDL (part of the kdl package). The tf_conversions package contains tools to convert PoseStamped messages to and from PyKDL Frames. Wim -- -- Wim Meeussen Willow Garage Inc.