The Goal

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1. Add IK Rear Fix Bone

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  1. Clear all trasforms ⬆️

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  1. Select the bone front 3 tail ⬆️

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  1. Extrude a bone ⬆️

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  1. Change the extruded bone name ⬆️

2. Set IK Constraint Target

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  1. Change the IK bone of the bone rear 4 ⬆️

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