Why Your Character Is Stuck in T-Pose
The T-pose problem is the most common issue developers encounter when importing motion capture animations. Your character stands frozen in a T-pose instead of playing the animation. The cause is almost always the same: skeleton mismatch. The animation was authored for a skeleton with different bone names or hierarchy than your character. Here is how to fix it in both Unreal Engine 5 and Unity.
Why T-Pose Happens
Motion capture animation data is stored as rotations relative to a specific skeletal hierarchy. If the animation expects a bone named "pelvis" and your character has a bone named "Hips," the engine cannot map the animation data to the correct bones. The character defaults to its bind pose — which is typically the T-pose it was rigged in.
An animation retargeting fix is usually needed when imported mocap data causes your character to bind in a T-pose rather than the expected A-pose.
Fixing T-Pose in Unreal Engine 5
Option 1: Assign the Correct Skeleton at Import
The simplest fix is to assign the correct skeleton at import time. When the FBX Import Options dialog appears:
- Under "Skeleton," select your existing skeleton asset (e.g., SK_Mannequin_Skeleton).
- If the bone names match, UE5 will map the animation data correctly and no retargeting is needed.
MoCap Online UE5-format packs are built for the UE5 Mannequin skeleton. If your character uses that skeleton, this is all you need.
Option 2: IK Retargeter for Different Skeletons
If your character uses a different skeleton (custom bone names, different hierarchy), use the IK Retargeter:
- Create an IK Rig asset for your source skeleton (the animation's skeleton) and define full-body IK chains.
- Create an IK Rig asset for your target skeleton (your character's skeleton) with matching chain names.
- Create an IK Retargeter referencing both IK Rigs.
- In the Retargeter editor, align the retarget pose (A-pose vs T-pose if needed) and verify chain mappings.
- Export the retargeted animations via Asset Browser > right-click > Export Animations.
Check: Is the Skeleton Wrong or the Pose?
If bones are mapped but the character is deforming incorrectly, the issue may be a pose mismatch. An animation captured in T-pose and applied to an A-pose character (or vice versa) will produce shoulder/arm errors. Fix this by adjusting the retarget pose in the IK Retargeter to match the bind pose of your character.
Fixing T-Pose in Unity
Option 1: Use Humanoid Rig Type
Unity's Humanoid rig system auto-retargets between any two humanoid skeletons:
- Select the FBX in the Project panel.
- Open the Rig tab in the Inspector.
- Set Animation Type to "Humanoid."
- Click "Configure" and verify the bone mapping (Unity auto-detects most standard rigs).
- Apply. Unity will now retarget this animation to any other Humanoid-typed character.
This is Unity's built-in solution and works for the vast majority of standard humanoid mocap packs.
Option 2: Generic Rig with Matching Skeleton
If you are using a "Generic" rig type, the animation bone names must match exactly. Use the same skeleton for all animation imports, or switch to Humanoid rig type which handles the bone-name difference automatically.
Preventing T-Pose Issues
- Use format packs built for your target engine (UE5-format packs for Unreal, Humanoid-compatible FBX for Unity).
- MoCap Online provides format-specific exports for UE5, Unity, and Blender to minimize retargeting overhead.
- Test the pipeline with one animation before importing an entire pack.
- Download the free animation pack to verify format compatibility with your character before purchasing.
Still Having Issues?
See also: animation retargeting guide and UE5 IK Retargeter setup. Browse the complete UE5 mocap integration guide for the full import-to-AnimBlueprint workflow, or the walk cycle animation setup guide for Unity Animator Controller setup with blend trees.
A-Pose vs. T-Pose: Why Both Exist and How They Affect Retargeting
The T-pose (arms at exactly 90 degrees from the body) and A-pose (arms at approximately 45 degrees, angled slightly downward) are both common rest poses for humanoid characters. The difference between them causes retargeting artifacts when source animations and target characters are not aligned to the same rest pose.
Why the A-pose replaced T-pose in many pipelines. The T-pose is technically clean to rig — all bone axes align with world axes, making weight painting predictable. But it is a physically extreme position. When a character rigged in T-pose runs a locomotion cycle, the arms travel from an extreme stretch to a natural carry position on every stride, which amplifies small deformation errors in the shoulder mesh. The A-pose keeps arm angle closer to the natural carry position, reducing the range skin weights must handle during typical gameplay animation and producing cleaner shoulder deformation in locomotion.
How the rest pose affects retargeting results. When retargeting animation from one skeleton to another, the retargeter calculates bone rotations relative to each skeleton's rest pose. If the source animation was authored for a T-pose skeleton and the target character uses an A-pose, the shoulder and upper arm chains will be offset in the result — arms that hang too low, rotate outward, or produce incorrect weight during locomotion. The fix is to define matching retarget poses in both IK Rigs before running the retargeter. In UE5's IK Retargeter, the "Edit Retarget Pose" mode lets you pose both source and target into the same rest position before the chain mapping runs.
Troubleshooting checklist for persistent T-pose problems.
- Verify skeleton assignment at import — the animation and target character must reference the same skeleton asset
- Check whether bind pose mismatches exist between source and target (T-pose vs. A-pose mismatch is the most common cause of arm artifacts)
- In UE5 IK Retargeter: confirm retarget pose alignment — even a 5-degree arm angle difference produces visible artifacts in locomotion
- In Unity Humanoid: use Configure Avatar to manually verify shoulder and upper arm bone assignments if auto-mapping produces wrong rotations
- Test one animation before retargeting a full library — confirm the retargeter produces clean results on a walk cycle before batch-processing 100+ clips
Systematic T-Pose Debugging: Reference Pose Mismatch, Hierarchy Divergence, and IK Conflicts
Most T-pose problems at animation retargeting have one of three root causes: a reference pose mismatch between source and target skeletons, a bone hierarchy divergence where the source skeleton has bones that the target does not (or vice versa), or a conflict between the retarget mapping and IK override settings applied to the target character. Reference pose mismatch is the most common — it occurs when the source animation was captured with the skeleton in a T-pose and the target character's bind pose is an A-pose. When the retarget system tries to map rotations from a T-pose-referenced source to an A-pose-referenced target, the arm rotations offset by the angular difference between the two rest positions, resulting in arms that hang slightly wrong at all times. The fix is always to set the retarget base pose on the source skeleton to match the target's rest position before establishing any bone mappings — this tells the retargeter to treat the T-pose reference as equivalent to the target's A-pose, eliminating the constant offset.
Bone hierarchy divergence is a subtler problem that manifests as specific body regions looking correct while others are frozen in the reference pose. When the target skeleton has a twist bone chain (forearm twist, upper arm twist) that the source skeleton lacks, the retargeter has no source data for those bones and leaves them in their bind pose rotation. On a character with forearm twist bones, this produces the classic forearm stick-out artifact where the lower arm refuses to follow the wrist rotation. The correct fix is not to map arbitrary source bones to the twist bones — this produces incorrect but not obviously wrong results that are hard to detect in production. Instead, drive the twist bones procedurally: use Unreal Engine's AnimDynamics or Unity's procedural IK to distribute the wrist rotation across the twist chain after the retarget, which produces physically correct twist behavior regardless of whether the source capture included it.
IK override conflicts appear when a target character has full-body IK (FBIK) or foot IK enabled at the animation level and the retarget is applied before the IK solves. In this case, the retarget correctly positions the feet based on the captured data, but the IK solver then overrides those positions to match the floor surface, creating a conflict where the animation data and the IK solution fight each other every frame. The result is jittery foot placement that looks correct in the preview but breaks at runtime when the character moves over non-flat geometry. The solution is to evaluate the retarget before foot IK — ensure that the retarget node in the Animation Blueprint or Animator Controller is evaluated before the IK nodes in the execution order. The retarget provides the base foot positions; the IK adjusts from those positions, rather than from the bind pose.
T-Pose Prevention Checklist: Setup Steps That Eliminate Most Retargeting Problems
Most T-pose retargeting problems can be prevented with a five-step setup checklist before any bone mapping is established. Step one: verify the source skeleton's bind pose matches the reference pose used during animation capture. For most commercial motion capture packs, this means confirming the source skeleton is in a standard T-pose — arms horizontal, palms facing down, feet flat. Step two: verify the target character's bind pose. If the character uses an A-pose bind, set the target character's retarget base pose to T-pose before mapping. Step three: compare bone naming conventions between source and target to identify any bones needing manual mapping.
Step four: confirm the skeleton hierarchy depth — source and target should have the same number of spine bones, shoulder chain bones, and finger joints. Step five: before creating any retarget asset, play one test clip on the source skeleton to confirm the source data is clean. An error in the source data looks identical to a retargeting error and is much faster to diagnose before the retarget is configured. This T-pose retargeting checklist takes 15-20 minutes and eliminates the most common setup errors in a single pass.