Point cloud stitching using ROS

Hi, I am utilizing a pair of manually calibrated stereo cameras (so, it's not a standard kinect) for obtaining pointclouds. Assuming I can obtain the (left) camera's post using an April Tag , I would like to know if there is a way to **stitch together point clouds in ROS, as long as I know the tf transform of the sensor?** (possibly using just command line or launch files ?) I have seen a few packages (not ROS packages) like [this](https://github.com/ethz-asl/ethzasl_icp_mapping). I have also seen a few posts on ROS forum (like [this](https://answers.ros.org/question/252632/how-to-correctly-build-an-octomap-using-a-series-of-registered-point-clouds/) but there are no accepted answers) **My use-case:** I would like to build an Octomap (from a pair of manually calibrated stereo cameras) from this and then use it for drone motion planning. Can someone provide any suggestions on where to start ? Thanks a lot.