IK / FABRIK blueprint tutorial for proper foot placement with capsule collision

[CptWallace]

FeetIK Progress - TwoBoneIK

Been bashing my head against this thread all week, managed to get a decent start with Feet IK so Ill post my findings below.

Thanks to Rhythm and , you guys rock.

I first used the FABRIK nodes but wasn’t able to get any decent results. The best I managed still had the knees bending forward and sideways giving my Character broken legs. ;(

I read this from -

@;291087

As far as I know, FABRIK ignores PHAT constraints.

So when I learned that, I figured without PHAT constraints I wouldn’t be able to lock the joint rotation to prevent overbending (without editing the C++ code for FABRIK).

With that, I switched back to TwoBoneIK, but the default skeleton in UE4 doesn’t have the required bones I needed for the Right and Left knee pit.

So on the advice of Rythm -

@RhythmScript;192228

I recommend manually setting the pit location using the forward vector of the foot bone (the knee pit should be some Z value above a space several units in front of the toes; typically the human leg does not rotate at the foot, so your knees usually face your toes).

I did just that. I added the forward vector of the capsule component to the location of the foot socket and offset the vector on the Z to give me a rough point in front of the characters knee.

Bit hacky but the effect worked without having to mess with the default skeleton.

Still have more work to do to fix the rotation of the foot and sell the overall effect, but this is my progress so far!

Also need to implement an animation function on n008`s advice and get the anim lerps off the tick -

@n00854180t;406913

you might try setting it up so that it doesn’t continuously try to find a new IK position for the foot if it’s found one and there hasn’t been any movement.

My blueprints are exactly the same as with a slight alteration in the AnimBP to get the vector for the Right and Left knee, like in the image below

Implemented this on a ThirdPersonTemplate project in 4.10, all fine!