# Havok memory access out of bounds

**URL:** <https://forum.babylonjs.com/t/havok-memory-access-out-of-bounds/40153>\
**Category:** Bugs\
**Created:** [April 24, 2023, 8:34am UTC](https://forum.babylonjs.com/t/havok-memory-access-out-of-bounds/40153 "2023-04-24T08:34:27Z")\
**Posts on this page:** 1\
**Page:** 2

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**Author:** ![aWeirdo](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/aweirdo/32/52_2.png) [@aWeirdo](https://forum.babylonjs.com/u/aWeirdo)\
**Post date:** [May 2, 2023, 5:36pm UTC](https://forum.babylonjs.com/t/havok-memory-access-out-of-bounds/40153/21 "2023-05-02T17:36:41Z")

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Hi @potato_noob  
You can’t add a constraint to a single body / aka to itself.  
I’m guessing the out-of-memory error is a recursive loop of sorts.

As discovered here:

> [@"moveWithCollisions" with havoc?](https://forum.babylonjs.com/t/movewithcollisions-with-havoc/40118/):
>
> Hey team, What’s the best method to setup meshes to work simular to “mesh.moveWithCollisions” using Havoc? Here i tried something very simple, any key makes the dummy run forward and push the sphere. But what if i want the sphere to be static? i give it mass 0 and dummy pass straight through it! Same for the ground mesh if i add gravity to the dummy’s velocity, falls straight through the ground mesh slight_smile Any thoughts? Edit; Digging a bit further in the docs, it seems because i…

You can use a constraint as you are doing now, but with a parent

> **[Babylon.js Playground](https://playground.babylonjs.com/#V9M1EL%2331)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL 3D scenes

Or you can set the character “imposter’s” velocity to 0

> **[Babylon.js Playground](https://playground.babylonjs.com/#V9M1EL%2330)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL 3D scenes

@Cedric mentioned in the topic above that Havoc comes with a built-in character controller aswell!  
But it won’t be in BabylonJs yet for some months.

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