Question about rotation in annotation files

[RealYuWang]

Hi there,

First of all, thank you for your great work!
I'm trying to figure out how the rotation in the annotation file was obtained. According to your description, "We define the rotation of objects around the LiDAR’s negative vertical ( -Z) axis" So I drew a BEV graph and the reference system is LiDAR. Is $\theta$ in it the rotation?