I am trying to make a Retro Tenis Game in Unity2D but I have some issues with the colliding system. My controller does not collide with the walls. It goes through them. It should stop in the wall like pic1 but it goes through it like pic2. Can anyone help me, please?
UPDATE#1: I added a RigidBody component but it does not fix it. (pic3)
You shouldn't use the colliding system for this purpose. It would be much better that the script in charge of moving your paddle was able to control its maximum and minimum height too (note that the screen size can change, and the paddles should move at different heights depending on the screen size).
Although if you want to do it with the collision system and "walls" that limit the space of the paddles, both the "walls" and the paddles need to have a correctly positioned BoxCollider2D and the paddles an extra kinematic Rigidbody2D too (as they can move).
Also make sure to move the paddles using physics and not modifying its position with transform.position (see Rigidbody2D.MovePosition)
Edit: Unity2D physics system is rather a complicated topic and difficult to get it well on your own. I'd suggest to learn the basics in the Unity Learning Platform. You could start with this project.
You need add RigidBody2D to your "circle"
