In Unity 5, I have a player shooting a projectile in aim to hit a boss, and inflict damage upon contact with the projectile. Though for some reason, the projectile and boss aren't colliding with each other.

I've done the following;

  • Made sure that both the projectile and boss have a BoxCollider 2D and Rigidbody 2D
  • Made sure that they're on the same Z-Index and on the same layer
  • Tried to Debug.Log() if there's any collision (there isn't)
  • Made sure I'm using OnCollisionEnter2D on the boss' health script
  • Compared the syntax I use with another collision (where the player collides with an object and dies - this works perfectly fine).

However, none of these seem to be working.
This is the boss' health script:

void OnCollisionEnter2D (Collision2D coll)
    bosshealth -= 1;

Here is the projectile prefab:
projectile prefab
And the boss prefab:
boss prefab

Does anyone have a clue as to why they're not colliding? the projectile just glides over the boss

EDIT: I found a temporary fix! Disabling the Kinematics of the boss allows for both objects to collide, and successfully display a debug message! Just a problem though; I don't want the boss to freely float around in space. I use the kinematic to ensure it stays put at all times until told to by scripts.

Is there a way to get around not having to disable the kinematics?

EDIT 2: Then again, I am removing the projectiles on impact anyway, so the actual boss doesn't move, but that seems dirty :/

  • \$\begingroup\$ Found a temporary solution - see edit. \$\endgroup\$
    – davidpox
    Dec 3, 2015 at 23:58
  • 1
    \$\begingroup\$ See the Collision Action Matrix on this page from the Unity docs: two kinematic bodies colliding does not call collision event functions. However, if you change your bullets so IsTrigger == true, then OnTriggerEnter2D will be called. \$\endgroup\$
    – DMGregory
    Dec 4, 2015 at 0:50
  • \$\begingroup\$ I see, thanks! I guess it makes sense. I've set the projectile as a non-kinematic now, and I'll work it from there \$\endgroup\$
    – davidpox
    Dec 4, 2015 at 0:53
  • 1
    \$\begingroup\$ Feel free to add an Answer with the fix you've found, so others can use it for reference. After a delay, you'll be able to mark your own answer as Accepted. \$\endgroup\$
    – DMGregory
    Dec 4, 2015 at 1:18

1 Answer 1


Thanks to @DMGregory for enlightening me on this.

It turns out that you can't collide objects that both have "Is Kinematic" enabled. To get around this personally, I just unchecked "Is Kinematic" from the projectile and set it's gravity to 0, so it doesn't fly down.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .