While developing our current project (TLS), we encountered a specific regression in Unreal Engine 5.7.4 regarding the IK Rig Retargeting logic. This is critical for anyone moving from “Indie-Dev” standards to high-fidelity singleplayer architecture.
The Problem: We noticed significant bone-roll inaccuracies and leg-snapping when retargeting locomotion sets to custom rigs. The default solvers often struggle with proportional offsets, leading to micro-stutters and mesh deformation in high-resolution environments.
The SheychX Dynamics Fix (SD-V5.0 Optimized):
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Two Bone IK Precision: To ensure the IK solvers (especially for legs and arms) operate correctly, you must manually override the Translation Retargeting settings.
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The Fix: Within the Skeleton Editor, locate the affected bones in the hierarchy. You must switch the Translation Retargeting Mode from
AnimationtoSkeleton. -
Why: This ensures the bone maintains its relative position based on the target skeleton’s proportions, preventing the “stretching” effect caused by source animation data that doesn’t match your rig’s scale.
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Bone Chain Override: In the IK Rig, manually define the Spine and Pelvis chains and set the Translation Mode to
Globally Scaledwhile forcing the Rotation Mode toInterpolated (Absolute). -
C++ Hook: For those with source access, we recommend overriding the
URetargetChainSettingsto inject a precision buffer. This prevents the solver from “snapping” when the delta between source and target is below a certain epsilon.
Human Excellence in Architecture: At SheychX Dynamics, we solve what others fear. Technical debt starts with ignoring these “minor” retargeting glitches. We ensure every frame of Project TLS reflects the stability of our SD-V5.0-AUTHORITY core.
Has anyone else noticed that the 5.7.4 Two Bone IK solver reacts differently to sub-stepping when physics-based blending is active?
Lead Architect Scheych Technical Lead Architect | SheychX Dynamics | SDX