Thanks for your work. when I reproduct it,following the step in the readme, I finished all the steps for Building SG-SLAM successfully , but when I run and test, it occur some problems.
roslaunch octomap.launch show that:

[WARN] [1681106496.736057330]: Nothing to publish, octree is empty
and Rviz has nothing to show.

the test instrutions are the follows from Readme

roscore
cd SG-SLAM/src/octomap_server/launch
roslaunch octomap.launch
roslaunch transform.launch
rviz
cd SG-SLAM/src/sg-slam/
./run_tum_walking_xyz.sh