# Using a DAE mesh for collision

**URL:** <https://forum.defold.com/t/using-a-dae-mesh-for-collision/69434>\
**Category:** The Defoldmine\
**Created:** [October 9, 2021, 3:54am UTC](https://forum.defold.com/t/using-a-dae-mesh-for-collision/69434 "2021-10-09T03:54:31Z")\
**Posts on this page:** 1\
**Showing post:** 3

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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:** [January 21, 2022, 12:27pm UTC](https://forum.defold.com/t/using-a-dae-mesh-for-collision/69434/3 "2022-01-21T12:27:04Z")

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Thank you for the great tool!

While making a 3d game with Defold, I found that Bullet Physics has a parameter named “Collision Margin”. Its value is [0.04](https://github.com/defold/defold/blob/1ae302ec33d4514408c04ad3ae5d3c1efe2057bd/external/bullet3d/package/bullet-2.77/src/BulletCollision/CollisionShapes/btCollisionMargin.h#L21) in Defold. Why? Take a look at the Bullet Physics manual:

 ![image](https://forum-defold-uploads.b-cdn.net/original/3X/2/7/27ca9188a2ba5bbcfd0a601027896c39f1384400.png)

You should take it into account if you are going to use custom collision shapes in Defold. In Blender, you can use [the Shrinkwrap modifier that has the “Offset” parameter](https://docs.blender.org/manual/en/latest/modeling/modifiers/deform/shrinkwrap.html).

Without that, there is a noticeable offset between physical objects:

 ![image](https://forum-defold-uploads.b-cdn.net/original/3X/2/8/2805118e1e88c5895268f5ce597287f19baf9367.png)

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