Resolved How to make a script activation zone?

Hello everyone.
I read about OnTriggerEnter. But I am not using the Rigidbody component. What other ways are there to make a script activation zone?
I came up with another way. Check in each frame whether the point lies in the circle. Is this method good? Is there a ready-made script with a formula for a circle and a rectangle?

 

Circle is just distance (Vector3.Distance()) compared to radius.

Rectangles are just min / max on all the axes. If the Rectangle is not axis aligned you would need to transform the point, perhaps with Transform.TransformPoint(), to match first.

Experiment in isolation before you try to use it in game.

 

Thanks for the answer. For now, I'll use the circle.