Do 2D triggers pass through each other with continuous collision detection without OnTriggerEnter?

I believe that continuous collision detection is broken in at least Unity 5.3.5. Even if it's on, the objects still pass through continuous collision detection is on. It happens when a Rigidbody2D has continuous collision detection and is supposed to hit a normal BoxCollider2D (without a Rigidbody2D). The object will still pass through!

Anyone else experienced this? Is this normal? The documentation (https://docs.unity3d.com/ScriptReference/CollisionDetectionMode2D.Continuous.html) seems to suggest this is a bug.

I've attached a quick example showing the problem.

 

Your object needs a non-kinematic rigid body in order for the physics engine to simulate forces that keep the two objects apart.

 

That's the case. It's a non-kinematic Rigidbody2D with a trigger CircleCollider2D attached to it. It should trigger OnTriggerEnter2D() when passing through the object, no?

 

You did point me in the right direction though - this only happens with triggers. Maybe continuous collision detection does not work for triggers?

 

No, you need a rigidbody on each object. (EDIT: at least, I think this is the case. I'm not at my development machine right now or I'd give it a try)

 

You definitely don't if the moving object is not a trigger. Then it just works if the wall is not a rigidbody. So I don't think that's the problem here.

 

Got it, that's good to know. You must be right, it's got to be the trigger flag.