So, I’ve gotten my metahuman to work with the Game Animation Sample Project. However, one issue I’m running into that no one seems to talk about, or even mention is the posture, clawed hands, and problems with scaling. I’m using a female metahuman for a character I’m working on. And as someone who doesn’t really do character stuff much, and more of an environment art. I’m not really wanting to create a whole animation system from scratch. However, a few issues arise when I set it up. I’m using UE5.8.2, however the problem persists through out all engine versions. One, my character is scaled up, the posture is hunched over, and the fingers are more clawed and curled. I notice that the other metahumans, and even the echo character don’t have this problem. How do I go about fixing this? Because, no tutorials, nor any documentation talk about this.
Hello @Shinno9301
Thank you for reaching out to the Unreal Engine Community Forums. It looks like integrating MetaHumans with specific animation systems and rigs can cause some technical hurdles, specifically skeleton retargeting, IK rig offsets, and bone scaling.
The issues you are having with the hunched posture, clawed/curled fingers, and unintended scale distortion, are all common side effects of retargeting motion data between skeletons with different reference poses, rest bone rotations, and IK chain setups.
Below is a technical breakdown as to why this occurs, and a step-by-step solution to get your female metaHuman working in conjunction with the Game Animation Sample setup.
Retarget Pose Mismatch (Hunched Posture & Curled Fingers):
The Game Animation Sample uses the Mannequin skeleton (Manny/Quinn) or Echo, which have a slightly different default Retarget Reference Pose than their MetaHuman counterparts, in particular the spine, shoulders, and default finger curl.
This means that when an IK Retargeter (RTG_) is used to transfer animation data, any deviation from the target skeleton’s Retarget Base Pose will result in an offset being applied somewhere in the chain, this often takes the form of slouched shoulders, hunched spine, or ‘clawed’ fingers.
Bone Translation Retargeting Settings (Scaling & Distortion):
MetaHuman skeletons have a slightly different proportion chain for things like height (f_med_nrw), and if the Bone Translation setting is not changed to Animation in the Skeleton Editor for all bones that are not part of the root, it can cause floating joints, aberrant mesh scaling, and stretched torsos when retargeting.
IK Chains and Control Rig Offsets:
As mentioned in the previous section, MetaHumans use a special MetaHuman Control Rig, and have two separate skeletons for the ‘body’ and ‘head’, when driving these with Motion Matching or Animation Blueprints provided by the Game Animation Sample, missing FK/IK overrides for chains not supported by the target skeleton can cause hands and feet to snap incorrectly.
Step-by-Step Resolution Guide
Step 1: Adjust Bone Translation Retargeting Options
Open your MetaHuman Body Skeleton asset (e.g. metahuman_base_skel, or f_med_nrw_posture_Skeleton).
In the Skeleton Tree panel, open the drop-down menu (gear-icon), and open Show Retargeting Options.
Right-click on the Pelvis bone, and set the Translation Retargeting to Animation Scaling.
Right-click on the RootBone and set it to Animation.
Right-click on the Spine_01 bone, Recursively Set Translation Retargeting Skeleton (ensuring that all child bones; spine, arms, neck, fingers, legs, etc., are strictly set to Skeleton).
This is important to avoid having the source animation bones corrupting your MetaHuman’s proportional scale.
Step 2: Align Retarget Base Pose in the IK Retargeter (RTG_)
Open the IK Retargeter asset, set up between the Game Animation Sample source character, and your MetaHuman (RTG_Mannequin_To_MetaHuman etc.)
Set the view mode to Edit Retarget Pose.
Look at the fingers, spine, and clavicles of both meshes.
Fingers: Straighten your MetaHuman’s fingers in the retarget pose editor, so they match the exact extension angle of the source mannequin.
Shoulders/Spine: Rotate the clavicle_l, and clavicle_r slightly back/up, to remove the hunched posture. Make sure that spine_01 up to spine_05 are straightened upright.
Click Create / Save Pose, and set it as the default Retarget Base Pose.
Step 3: Set up Chain Mapping, and IK settings
In the IK Retargeter, look at the Target panel on the right-hand side.
Select the Left Hand / Right Hand chains:
Make sure that the FK Translation Mode is set to Absolute, or Globally Scaled, depending on if you want the hand-lengths to stretch or not.
Under the IK Goal settings for hands and feet, make sure that the Blend To Source values are balanced out, to prevent the arm / leg from being forced to have an offset-stretch.
Under the Finger-chains, make sure that every single individual finger-chain (Index, Middle, Ring, Pinky, Thumb) is accurately mapped from source to target, and that none of the leaf-bones are missing.
Step 4: Make sure the MetaHuman Modular Mesh is aligned correctly
Open your MetaHuman Character Blueprint (BP_MetaHuman).
Select the Feet, and Torso components, under the Mesh hierarchy.
Make sure that the Master Pose Component (or Set Leader Pose Component in UE5.8+), is binding the child skeletal-meshes (Face, Torso, Legs, Feet, etc.) correctly to the main Body-component.
Make sure that scale-values on all mesh-components are set to (1.0, 1.0, 1.0)
Epic Documentation links:
This has been very helpful thank you! The only issue now that I’m facing is that my character kind of get’s stretched to match the source UEFN skeleton, and potentially squished inwards.
Glad to hear the initial repositioning suggestions worked!
The stretching and “squishing inward” you’re witnessing during retargeting is due to the RTG_ forcing the bone translations of the source UEFN/Mannequin skeleton onto your MetaHuman skeleton, overriding the latter’s natural proportion scale.
Due to a MetaHuman being a specific height/body with preset values (medium, tall, female, male variations), the unadjusted translations of mannequin motion are forcing the joints (shoulders, pelvis, hips, limbs) of the target skeleton to assume the source’s absolute proportional values.
I present the following detailed breakdown as well as step-by-step resolution for the scale deformation/compression during IK retargeting.
Cause Breakdown
FK Chain Translation Mode Override (Stretching/Squishing):
By default, many retarget chains are set to copy Absolute translation from the source bones. Since the source skeleton in your case has wider shoulders or longer torso than your MetaHuman, the target joints get pulled outward/pushed inward to match the absolute world-space displacement of the source skeleton.
IK Goal Stretching & Pole Vector Offsets:
By their very nature, when IK Chains (Legs and Arms) are active, the IK Goals force absolute spatial positioning for the feet and hands. If the IK Goal distance is longer/narrower than your MetaHuman’s actual arm/leg length, the limb joints will compress inward/stretch unnaturally to bridge the gap.
Pelvis and Root Scale Inheritance:
In UE5’s IK Retargeter system, if the Root Settings are set to scale motion globally without proper proportion scaling, vertical translation shifts on the root bone will force the entire mesh to stretch vertically or collapse horizontally.
Step-by-Step Resolution Guide
Step 1: Modify FK Chain Translation Modes in the IK Retargeter
Open up your IK Retargeter asset (RTG_ file transferring from UEFN/Mannequin to your MetaHuman).
Right panel under Target > Chain Mapping.
Select all your main limb and spine chains (Spine, LeftArm, RightArm, LeftLeg, RightLeg, LeftClayicle, RightClavicle).
Details panel under FK Settings > FK Translation Mode:
Change Absolute/None to Globally Scaled or Scaled.
Globally Scaled calculates the relative ratio between the source bone length and the target bone length, preserving your MetaHuman’s exact mesh proportions rather than forcing the UEFN skeleton’s bone lengths.
Step 2: Configure Root and Pelvis Retarget Settings
Select the Root chain in the Target panel in the IK Retargeter.
Under Root Settings in the Details panel:
Set Blend to Source for Translation to 1.0.
Set Scale Horizontal Motion and Scale Vertical Motion according to your mesh proportion preferences (typically having a global bone scaling will automatically balance this out).
If the torso is still squished or pulled down, then select the Pelvis chain and change FK Translation Mode to Globally Scaled.
Step 3: Adjust IK Goals and IK Alpha Blends
In the IK Retargeter asset, select each IK Goal in the viewport or hierarchy (IK_Foot_L, IK_Foot_R, IK_Hand_L, IK_Hand_R).
Under the Details panel for each IK Goal:
Locate IK Translation Mode and make sure it’s set to Automatic or Globally Scaled.
If the arms or legs are bowing inwards, be sure to look at the Pole Vector settings for the elbow and knee goals to make sure the target solver alignment isn’t collapsing the joint plane.
If the fingers/hands are stretching towards the center, adjust Blend To Source on the Hand IK Goals a little down (e.g., 0.8 to 0.9) so that it allows the FK motion to take precedence over strict spatial IK targeting.
Step 4: Verify Bone Translation Retargeting in Skeleton Editor
Open up your MetaHuman Skeleton asset (metahuman_base_skel).
Make sure that Show Retargeting Options is enabled in the Skeleton Tree.
Verify the following settings are re-set:
Root: Animation
Pelvis: Animation Scaling (or Animation Relative)
All other bones (Spine, Thigh, Clavicle, Limbs, Fingers): Skeleton
Recommended Resources & Verification
In order to verify that everything is working correctly, you need to play the animation sequence in the IK Retargeter editor and look at both the Source and Target preview windows. Your MetaHuman must move as the source mesh moves without collapsing, clipping, or stretching limbs and other parts of the model.
Please let me know if changing FK Translation Mode to Globally Scaled helps with the stretching proportions! If you are still getting slight twisting around the shoulders or hips feel free to share a screenshot of your Chain Mapping details tab!