About function get_ee_pose()

[YanJiaHuan]

Hi, here line 998 of furniture_sim_env.py you wrote the get end-effector function, and get:
hand_pos - base_pos -> ee_pos
hand_quat -> ee_quat
My question is (Sorry, but already confused with coordinate transform): why ee_pos is a relative, and ee_quat is what it is from hand_quat.
Can you help me figure out that? Thanks