# How to run collision callback only on collision enter in new havok physics

**URL:** <https://forum.babylonjs.com/t/how-to-run-collision-callback-only-on-collision-enter-in-new-havok-physics/40765>\
**Category:** Questions\
**Tags:** physics, havok\
**Created:** [May 13, 2023, 5:36pm UTC](https://forum.babylonjs.com/t/how-to-run-collision-callback-only-on-collision-enter-in-new-havok-physics/40765 "2023-05-13T17:36:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AmirHo3ein](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/amirho3ein/32/32020_2.png) [@AmirHo3ein](https://forum.babylonjs.com/u/AmirHo3ein)\
**Post date:** [May 13, 2023, 5:36pm UTC](https://forum.babylonjs.com/t/how-to-run-collision-callback-only-on-collision-enter-in-new-havok-physics/40765/1 "2023-05-13T17:36:23Z")

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Hi, Collision callback is running continuously now, and I want it to be run only on collision enter. i’ve used setEventMask method but it’s not working!

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<div class="post-metadata">

**Author:** ![Raggar](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/raggar/32/20672_2.png) [@Raggar](https://forum.babylonjs.com/u/Raggar)\
**Post date:** [May 13, 2023, 6:54pm UTC](https://forum.babylonjs.com/t/how-to-run-collision-callback-only-on-collision-enter-in-new-havok-physics/40765/2 "2023-05-13T18:54:26Z")

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Make sure to set the EventMask on the body AFTER the call to setCollisionCallbackEnabled, as this function creates a mask with the bits of all three states set by default