How to remove IK Target after a certain point without breaking the animation?

Question

I'm creating a sitting animation for a dog. I used an IK target to lock his right leg to a specific location when I was animating his left leg.

Everything is fine and the animation is going how I want it to. Now I've reached a point where I'm done with left leg and I want to start to move his right leg.

The IK Target doesn't let me do it. I'm looking for a way to remove this IK target but keep all the effects it had on my animation from frame 1 to frame 31.

I tried animating the right leg by moving the IK target, but it didn't work as I expected it to, for example, the bone doesn't rotate the way I want when I try to rotate it using its IK target. Other than that, moving the IK Target also moves other parts because they're not locked in a location with an IK.

Can someone please help me with this?

Answer 1

I found a solution to that.

Insert all the keyframes, Pose Mode > AA > I > Visual Location, Rotation & Scale Then click on pose on the left top corner of the 3d viewport, Animation > Bake Action Tick, Only selected Bones (because you pressed double A to select everything), visual keying, and clear constraints. enter your start and end frame and hit OK

It'll bake an animation exactly like what you created and unlocks all the IK targets.

from now, you can make new IK Targets and do the rest of your animation.

Hope it helps someone

P.S. Overwrite current action can help you append more baked animation to your timeline. for example, you can use ik to hold a bone in a place and animate a part of your rig, then unlock it and bake the animation, then lock another part of your rig and animate another part. For doing that, you need to set the start frame in the bake action to the end frame of the previously baked animation and enable overwrite current action. this will append baked animations to the end of the timeline.

Answer 2

A non-destructive way to achieve this is to simply have two IK constraints on the bones you want to have IK with and without pole targets. Each Ik constraint will be set up the same, except for the pole target and especially the weight.

Then during your animation, you can animate the weights values to switch the constraints on and off.

Making some UI

You can also push this further by having a controller or a custom property somewhere to control the switching for you so that you have only one value to animate instead of two.

For example, if using a custom property on the foot bone:

Right-click the value → copy as driver:

Back on the IK bone constraints, right-click the weight values and click Paste driver :

On the constraint you want to be OFF when the custom property is at 1 , right-click the weight value that is purple and select Open Driver Editor (I named my property "IK target", so it makes sense to have the constraint without pole OFF when this properties is on 1) :

In the driver editor, make sure you select only the keys of the curve from the constraint we want to edit (mine will be the IK no pole). Hit the "Cursor to selection" button so the cursor snaps in the middle of the keyframe. Then open the Mirror menu by hitting Ctrl M → and chose the option "by values around cursor value":

This would have effectively flipped the curve, meaning when your custom property will go from 0 to 1, this constraint weight will go from 1 to 0.