# Custom 3D collision shape

**URL:** <https://forum.defold.com/t/custom-3d-collision-shape/12505>\
**Category:** Questions\
**Created:** [October 13, 2017, 9:40am UTC](https://forum.defold.com/t/custom-3d-collision-shape/12505 "2017-10-13T09:40:57Z")\
**Posts on this page:** 1\
**Showing post:** 16

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**Author:** ![aglitchman](https://forum-defold.b-cdn.net/user_avatar/forum.defold.com/aglitchman/32/19432_2.png) [@aglitchman](https://forum.defold.com/u/aglitchman)\
**Post date:** [May 16, 2021, 9:43pm UTC](https://forum.defold.com/t/custom-3d-collision-shape/12505/16 "2021-05-16T21:43:17Z")

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> [@astrochili](#):
>
> May be the random factor is a bad memory access or a floating point stuff? For example, it can be out of bounds in `vertices[i]` that gets an undefined behavior with random vertex data.

I managed to fix this issue, take a look:  
[https://github.com/defold/defold/pull/5817](https://github.com/defold/defold/pull/5817)

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