# AttachTo + ChildActorComponent breaks on static mesh actor BPs with physics enabled

**URL:** <https://forums.unrealengine.com/t/attachto-childactorcomponent-breaks-on-static-mesh-actor-bps-with-physics-enabled/327907>\
**Category:** World Creation\
**Tags:** UE4-8, unreal-engine, Physics, bug-report, Blueprint, question\
**Created:** [August 7, 2015, 4:26am UTC](https://forums.unrealengine.com/t/attachto-childactorcomponent-breaks-on-static-mesh-actor-bps-with-physics-enabled/327907 "2015-08-07T04:26:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![JAelwyn](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@JAelwyn](https://forums.unrealengine.com/u/JAelwyn)\
**Post date:** [August 7, 2015, 4:26am UTC](https://forums.unrealengine.com/t/attachto-childactorcomponent-breaks-on-static-mesh-actor-bps-with-physics-enabled/327907/1 "2015-08-07T04:26:58Z")

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This seems suspiciously similar to _parts_ of what was reported in [Collision and child actor - World Creation - Epic Developer Community Forums](https://answers.unrealengine.com/questions/232013/collision-and-child-actor.html) and [AttachTo not working on USphereComponent - Programming & Scripting - Epic Developer Community Forums](https://answers.unrealengine.com/questions/248957/attachto-not-working-on-uspherecomponent.html) – especially latter.

boil-down of it is that if I create a (moveable) static mesh actor BP that has physics enabled, and then try to use it by calling AddChildActorComponent + AttachTo targeting scene default root, AttachTo appears to completely ignore(?) its transform handling option, and treat it as if it were “keep world position”.

Steps to reproduce:

1. Create a BP extending StaticMeshActor
2. Set BP defaults to be movable, enable physics, and set collision presents accordingly
3. Add a tick event handler that applies a physics force (torque is main one I’ve tried at this point)
4. Create a BP extending Pawn
5. Add an event handler for play begin
6. To that event handler, add an AddChildActorComponent node set for manual attachment and a non-zero transform vector
7. Then add a node which attempts to attach that component to scene default component, set to keep relative transform
8. Place an instance of pawn BP into a level at some position other than origin, and hit play

Expected result: pawn should spawn into level, with static mesh BP offset from pawn origin by transform vector specified in step 6, in all cases

Actual result:

- If static mesh actor BP has physics disabled, it is spawned in correct location
- If static mesh actor BP has physics enabled, it is spawned at that offset from world origin, rather than pawn’s origin

I have a sample project that demonstrates this in multiple ways, but I wasn’t able to find a good guide for “how to provide an example project sanely” anywhere – if someone can point me at instructions for that, I will attach it.

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**Author:** ![JAelwyn](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@JAelwyn](https://forums.unrealengine.com/u/JAelwyn)\
**Post date:** [August 7, 2015, 4:30am UTC](https://forums.unrealengine.com/t/attachto-childactorcomponent-breaks-on-static-mesh-actor-bps-with-physics-enabled/327907/2 "2015-08-07T04:30:09Z")

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Of course, upon posting question, “similar questions” sidebar comes up with [ChildActor with physics spawns in incorrect location - World Creation - Epic Developer Community Forums](https://answers.unrealengine.com/questions/258978/childactor-with-physics-spawns-in-incorrect-locati.html) which appears to quite possibly be identical.

Why that never came up when I was searching for answers in first place, I have no idea, but it didn’t.

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**Author:** ![anonymous\_user\_33800a51](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_33800a51](https://forums.unrealengine.com/u/anonymous_user_33800a51)\
**Post date:** [August 7, 2015, 1:36pm UTC](https://forums.unrealengine.com/t/attachto-childactorcomponent-breaks-on-static-mesh-actor-bps-with-physics-enabled/327907/3 "2015-08-07T13:36:31Z")

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Hi JAelwyn,

Yes, I believe you’re experiencing same issue reported in ] (reported as UE-18762 in our bug tracking system). I’ve updated bug with your notes and I’ll post here if I see an update on it.

For future reference, best way to get a test project to us is to upload it someplace like Dropbox or Google Drive and then post a link for us.