hello, why these IK bones are not following the Source?? i really need help
Hi @LuBuSniper. let me know if I can help you with the problem.
I would first need to see the video because it appears as private and I can not see what the problem is. and if possible I would like to know a description of what the problem is.
I hope we can solve it together
Greetings
the video is not private now, do you have the same problem?
Hello @LuBuSniper,
First of all, thank you for sharing the video with us. Your explanation was extremely clear. Let’s see if we can help you with this issue.
This was an interesting and challenging question to solve because when I read it, I was also surprised by the error. I was sure it would work exactly as you had set up the retargeting, so I had the same doubt.
So, we worked on it, solved it, and even learned something new ourselves. And here is the solution:
The short and simple explanation:
We are going to add IK handles to the arms in both mannequins’ rigs (UE4 and UE5). Then, we will configure the mapping chain from the root of the IK system, align the initial poses, and activate IK in the IK Retargeter to ensure the bones maintain the same position. After that, all that’s left is to export the animations and enjoy.
Now, the detailed explanation:
1. How should we configure the mannequin?
Since you probably already have a full-body IK solver set up, we will need a new solver for the IK_hand_l chain.
The setup is very simple:
- Add a new Transform Solver.
- Select it, then right-click on ik_hand_l and add a new Goal, making sure it is associated with the new transform. (See Image 01)
NOTE: If more IK solvers are needed, repeat these steps for them, and also apply them to the second mannequin.
Finally, and most importantly, as shown in (Image 02), make sure to configure the IK chain so that it starts from ik_hand_root.
2. How to configure the retargeter?
Inside the IK Retargeter tool, we should:
- A) First of all, enable the IK Blend so that the IK controls follow the source instead of the FK controls. (See image for reference.)
- B) With the IK controls selected, set:
- Rotation Mode to One to One
- Translation Mode to Absolute
- This ensures the rotations are copied exactly from the source. (See image below for reference.)
Final adjustments if needed:
This setup should be enough, and in general, it shouldn’t present major issues. However, I noticed that there were still small differences in my animation. This was because the initial pose was too different.
So, here’s an extra step that may or may not be necessary in your case:
-
Enter the Retarget Pose editing mode at the top of the tool.
-
Select the Target and choose the second option: Auto Align All Bones.
-
However, since this also affects the feet’s orientation (which is not ideal), manually select the feet and, in the first Reset option, open the dropdown menu and choose Reset Selected Bone and Its Children to maintain the correct foot angle.
after:
Finally, all that’s left is to export the animations and enjoy.
ah, sorry, I did everything from manny to mannequin 4 because I didn’t have any animations loaded from 4. but the process is the same.
I hope this has been helpful!
Best regards! 
there is a jogging animation in ue4 folder in everything third person project. i tried all. I think my engine is broken. cuz it’s not moving at all. may i know which engine you are using? I mean which version. i wish you could record me a video from the begging. even though you did more than u had to, thank you. i can’t even sleep well because of this problem
Yes, no problem in passing you the info of what version I was using… I just checked and it is version 5.4.4
now in a moment I will also see if I can record a video with the process. I would be very happy to know that I was able to help you finally.
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i will download ue5.4 and waiting for the video😊, thank you so much
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Here is the Video as Promised
I couldn’t do it earlier because I was at work finishing some tasks.
I apologize for the silent video—it seems that OBS didn’t record my audio while I was explaining. However, I believe it’s still understandable.
At one point, I accidentally used Ctrl+Z (undo) and deleted the ik_foot_root, but in the end, I restored it, and everything worked again.
Anyway, I arrive at the result we intended.
I hope I was clear this time, and I wish you the best in finishing your project!
Have a great weekend!
Best regards
Likely, go back to the start and define the IK bones in the original retargeting definition - yes you need to expand and add the specidic IK bones.
Also, its obviously only going to transfer over via retargeting if the IK bones are animated - if you are using Epic stuff, then the animations, as I’m sure you already know, do not animate the IK bones…
Still, I’m 99% sure you are entierly missing the step where you define the retargeting setup.
I think you so that in the new version by not selecting the automatic option.
Give that a try before abything else.
thank you so much for your help, and sorry for replying to you late, my personal life isn’t going well.
here is the project itself. i doesn’t work for me at all, idk why ):
Hello @LuBuSniper. I didn’t want to leave you without an answer. I have a possible solution, but I don’t think we can use retargeting.
The main issue is that the bone hierarchy of both skeletons, specifically regarding the weapon bones, is very different. Even if we managed to fix the translations despite the hierarchy differences, we would likely have compatibility problems due to the initial rotations, and other animations might later generate strange rotations on the weapons.
I spent about two hours testing different types of IK setups and configurations. I even discussed it with a colleague at work, but the Weapon_r bone always ended up in the wrong place. And if Weapon_r seemed to be in the right position, the other bones, being relative to their parent, also ended up misaligned. The issue is that their positions should be absolute relative to the world. Tomorrow, if I have time, I’ll give it another couple of tries, but I’m not sure if it’s possible using Unreal’s retargeting system when the hierarchies are so different.
However, if what you need is to transfer the animation to your blue skeleton, I do have a simple solution that I know will work, but you would need to use another animation program such as Maya, Blender, or 3ds Max—whichever you feel most comfortable with.
What we can do is export the animation in our Target skeleton using retargeting, where it still uses the IK bones for the sword. Right now, it’s incorrect, but we’ll fix it.
Once we have the animation on the IK bones of our Target skeleton, and with our bones Weapon_r, T1, and T2 still without animation, we will take this FBX into our chosen animation software to edit the animation.
In your selected software, all we need to do is apply a Parent constraint without offset, using the following mapping:
- ik_hand_root → Weapon_r
- ik_hand_r → T1
- ik_hand_l → T2
In other words, Weapon_r should follow ik_hand_root.
With this setup, the new bones will always follow the IK bones without any issues, maintaining the correct positions and rotations exactly as in the Source skeleton’s animation.
Finally, the last step is to bake these three bones (Weapon_r, T1, T2), delete the constraints, export the animation, and re-import it into Unreal as an Animation Sequence for the blue skeleton.
I hope this explanation makes sense. If anything is unclear, let me know, and I’ll try to explain it again. But I believe this is the simplest and fastest solution.
Sorry that I couldn’t help much with the retargeting this time, but I hope I was able to solve the issue.
Best of luck with your project!
Best regards.
someone told me UE4 can do this. i tried all the everything, the last result i got was a close one but it was broken. i tried everything you said, but results are not good ): . i may have to wait until we get an update for unreal. because this is a bug
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