# What the hell is a slot?

**URL:** <https://forums.unrealengine.com/t/what-the-hell-is-a-slot/18095>\
**Category:** Character & Animation\
**Tags:** unreal-engine\
**Created:** [January 1, 2015, 10:34am UTC](https://forums.unrealengine.com/t/what-the-hell-is-a-slot/18095 "2015-01-01T10:34:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![zoombapup](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@zoombapup](https://forums.unrealengine.com/u/zoombapup)\
**Post date:** [January 1, 2015, 10:34am UTC](https://forums.unrealengine.com/t/what-the-hell-is-a-slot/18095/1 "2015-01-01T10:34:07Z")

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Ok, I’m confused.

What is a slot?

I don’t mean the attach point that you add to a skeleton. I understand that one.

The animation blueprint in shootergame blends in the third person aim blend space but then has a slot node after it which has “UpperBody” set. But what the hell does that Slot node do? I want to be able to blend only the specific parts of the skeleton that are contributing to the aiming, which I do right now by using a blend that allows me to specify a start bone and a depth. But is that what the SLOT thing was doing? What is the “UpperBody” and where is it defined?

Its kind of fascinating how fiddly all this stuff is. I’m doing a first/third person controller with cover taking/parkour/crouch/prone and the like and it amazes me how many things contribute to the overall animation. Things like additive loops for firing weapon knock-back and the like.

How do you guys work all this stuff out? I’d like to design some of this up-front because right now, so if anyone has any tips please share them.

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**Author:** ![anonymous\_user\_923c79df](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_923c79df](https://forums.unrealengine.com/u/anonymous_user_923c79df)\
**Post date:** [January 1, 2015, 11:51am UTC](https://forums.unrealengine.com/t/what-the-hell-is-a-slot/18095/2 "2015-01-01T11:51:18Z")

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The slot node is used in combination with a montage -\> In this series you learn everything about the UE4 animation tools (also explains how to use montages and slots) 🙂

[https://docs.unrealengine/latest/INT/Engine/Animation/AnimMontage/index.html#slots](https://docs.unrealengine/latest/INT/Engine/Animation/AnimMontage/index.html#slots)

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**Author:** ![zoombapup](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@zoombapup](https://forums.unrealengine.com/u/zoombapup)\
**Post date:** [January 1, 2015, 1:32pm UTC](https://forums.unrealengine.com/t/what-the-hell-is-a-slot/18095/3 "2015-01-01T13:32:29Z")

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> [@;199649](#):
>
> The slot node is used in combination with a montage -\> In this series you learn everything about the UE4 animation tools (also explains how to use montages and slots) 🙂
> 
> [https://docs.unrealengine/latest/INT/Engine/Animation/AnimMontage/index.html#slots](https://docs.unrealengine/latest/INT/Engine/Animation/AnimMontage/index.html#slots)

Riiight, I can see whats up now then. It was basically additively doing a montage on the upper body using the UpperBody slot and blending that with the cached base pose. Which makes sense. I thought for some reason it was doing a blend with the aim offset blend space.

Well there you go, I learnt something new! Thanks 🙂