static [FLayeredBoneBlendReference](API\Runtime\AnimGraphRuntime\FLayeredBoneBlendReference) SetBlendMask ( const [FAnimUpdateContext](API\Runtime\Engine\Animation\FAnimUpdateContext) & UpdateContext, const [FLayeredBoneBlendReference](API\Runtime\AnimGraphRuntime\FLayeredBoneBlendReference) & LayeredBoneBlend, int32 PoseIndex, [FName](API\Runtime\Core\UObject\FName) BlendMaskName )