### How can I get the direction for a square box component?

hi, everybody,
I made a square box. it is symmetric. The picture about my box shows in the ~~link:https://drive.google.com/file/d/1gqVz9CmSGdZlxI_jLgG9w-sPNqZueQf0/view?usp=sharing
~~link:https://drive.google.com/file/d/1gqVz9CmSGdZlxI_jLgG9w-sPNqZueQf0/view?usp=sharing

How can I get the direction of the square box?
Because I need to define a direction of the square box in my simulation.
for example, assuming the box is moving and a little bit rotation, and I want to calculate the distance of moving in the direction (eg. vertical of a side of the box) in 5 seconds. So, how we know the vertical of a side of the box?

I know how to get the position when the box is moving. But I have no idea how to get the direction (eg. vertical of a square box) of a component.

maybe this is not very clear. please write comments if you have any questions.

Thanks a lot!