Hi Soikot,
Please select the structure and click to edit it. All structures and structures groups have a “rotation” tab in the options (as figure below). You can choose the rotation axis for up to 3 different rotations.
You can also check the “rotation” tab description of the speciffic structure object, as: https://optics.ansys.com/hc/en-us/articles/360034901473-Rectangle-Simulation-Object
You are navigating away from the AIS Discovery experience