How do I keep an individual part of a rig completely still while the rest of the rig continues to move?

Question

I want to animate a character punching, but I want the fist to stop at the impact while the rest of the body continues to move. Is there some sort of anchoring mechanic? How do I put that into the keyframes?

Please be warned, I am both very new to Blender and a certified idiot. If you want to get through to me, you'll have to give me a direct tutorial or explain it in baby language.

Any help is greatly appreciated.

Answer 1

The thing you need is called "Inverse Kinematics" – often shortened to IK.

There are A LOT of videos on that topic, e.g. this one: =link=

Now - when you know what you need - just watch related videos.

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UPD: You can enable/disable IK during the animation.

In Pose Mode in the [Bone Constraints] tab you can edit IK's Influence:

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Influence is 0 – IK disabled

Influence is 1 – IK enabled

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You can animate this value:

1. Uncheck Only Show Selected (to see keyframes related to Influence)

2. Switch to the first frame of your animation (Shift+←):
3. Since you want IK disabled at first – set Influence to 0 and while hovering mouse cursor over that 0 – press I (this will create a keyframe for 0 value)
4. Then go to the frame, where IK should be switched
5. Set Influence to 1 and while hovering mouse cursor over that 1 – press I (this will create a keyframe for 1 value)
6. Now to make the switching instant – select all keyframes related to Influence, then RightMouseClick > Interpolation Mode > Constant :

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That's it.

By the way, you can switch IK not only once, but as many times as you want *by changing IK Influence from 0 to 1 and back from 1 to 0.