# Havok box debug drawing is slightly smaller than box

**URL:** <https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154>\
**Category:** Bugs\
**Tags:** havok\
**Created:** [October 26, 2025, 10:48pm UTC](https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154 "2025-10-26T22:48:01Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![regna](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/regna/32/23915_2.png) [@regna](https://forum.babylonjs.com/u/regna)\
**Post date:** [October 26, 2025, 10:48pm UTC](https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154/1 "2025-10-26T22:48:01Z")

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Please see the PG: [https://playground.babylonjs.com/#0U7AEA#8](https://playground.babylonjs.com/#0U7AEA#8)

Please note how Havok’s debug drawing of a box is slightly smaller than the box. I found that it’s always smaller by of 0.015 in width, height, and depth.

(Debug drawings look fine for other shapes, e.g. spheres.)

By chance, is there a margin of 0.015 internally in Havok’s debug drawing just for boxes?

(i.e. 0.015 baked into the result returned by`HP_Shape_CreateDebugDisplayGeometry()` and `HP_DebugGeometry_GetInfo()`?)

Thank you for your help!

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**Author:** ![Cedric](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/cedric/32/2742_2.png) [@Cedric](https://forum.babylonjs.com/u/Cedric)\
**Post date:** [October 27, 2025, 9:56am UTC](https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154/2 "2025-10-27T09:56:18Z")

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cc @eoin

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**Author:** ![eoin](https://avatars.discourse-cdn.com/v4/letter/e/f14d63/32.png) [@eoin](https://forum.babylonjs.com/u/eoin)\
**Post date:** [October 28, 2025, 12:14pm UTC](https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154/4 "2025-10-28T12:14:16Z")

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For performance and behavioral reasons, we shrink convex shapes and re-add that distance in with an additional radius; that value defaults to 1.5cm, but may be less if the object is smaller. When we added CreateDebugDisplayGeometry(), we chose not to add this radius back in, as doing so is a ton more calculation, which we wanted to avoid for a debug tool like that.

So, yes, it is expected to see a small difference like that; you’ll see it for most of our convex shapes - box, cylinder and convex hull.

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<div class="post-metadata">

**Author:** ![regna](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/regna/32/23915_2.png) [@regna](https://forum.babylonjs.com/u/regna)\
**Post date:** [October 28, 2025, 4:45pm UTC](https://forum.babylonjs.com/t/havok-box-debug-drawing-is-slightly-smaller-than-box/61154/5 "2025-10-28T16:45:19Z")

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Thank you so much, all! 😄