Strange results when using two bone ik

Development Character & Animation
1

So I’ve created a simple two bone ik with a pole vector control in maya (2018) and did some animation and the results I get are as I would expect:

I exported the skeletal mesh and animation into unreal (4.18) and set it up with a two bone ik, but I’m getting unexpected results:

In the videos you can see the mesh in unreal is twisting where in maya it’s not twisting.

I’m not sure if I’ve done something wrong.

Did I set up the two bone ik correctly?

This is the skeleton:
[ATTACH=JSON]{“data-align”:“none”,“data-size”:“full”,“data-tempid”:“temp_131550_1520433043670_803”,“title”:“ikTest_unreal_skeleton.jpg”}[/ATTACH]
https://forums.unrealengine.com/core/image/gif;base64
​

This is the anim blueprint:
[ATTACH=JSON]{“data-align”:“none”,“data-size”:“full”,“data-tempid”:“temp_131551_1520432938059_245”,“title”:“ikTest_unreal_animBlueprints.jpg”}[/ATTACH]
https://forums.unrealengine.com/core/image/gif;base64
​

These are the settings for the two bone ik:
[ATTACH=JSON]{“data-align”:“none”,“data-size”:“full”,“data-tempid”:“temp_131560_1520433086706_578”,“title”:“twoBoneIkSettings.jpg”}[/ATTACH]
https://forums.unrealengine.com/core/image/gif;base64
​

Thank you in advance!

Ryan

2

I think you have to manually set the rotations of your end joint maybe?
I had to do that with a ‘Transform/Modify Bone’ node in the Anim Blueprint.

3

I thought about something like that, but doing extra work to manually rotate the joints seems to go against what ik should give you.

I did a little test comparing results of Leg Ik to Two Bone Ik:
(The first part of the video is Leg Ik, the second part is Two Bone Ik)

When looking at the meshes, using Leg Ik seems to be working correctly, where using Two Bone Ik doesn’t seem to be working right.

My thought now is that maybe Two Bone Ik is broken.

4

Any more info on this? Is ‘Two Bone IK’ an older way of doing leg (or whatever) ik in ue4 and ‘Leg Ik’ should be preferred?