Hello, I have this structure.
None of these nodes emits the signal "body_entered" so I can't detect collisions?
I know that the node "area2D" emits the signal "body_entered" but I want to make sure that collisions with the structure that can be seen in the image cannot be detected.

I'm not sure, I think it should be able to detect collisions but none of the nodes emits the signal "body entered", I'm confused.
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Ok, so what happens is that bodies like kinematicBody2d detect collisions with other bodies that inherit from physicsBody but do not emit a signal when doing so, in addition, to detect those collisions they need the user to define their shape and this is done with CollisionShape2D.
It is understood.