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Choosing a Rig Framework

Why use this addon instead of Auto Rig Pro's Quick Rig?

Quick Rig constrains the RBF corrective bones as well as the swing and twist bones, and does its own setup for them. That setup does not match what the MetaHuman bones do in Unreal Engine.

The Character Control Rig addon instead gives you a control rig to pose and animate with, while piping the dependency graph updates to OpenRigLogic so the body evaluates against what is configured in the DNA. This is a 1-to-1 match with how the MetaHuman rig works in Unreal Engine and gives you high quality corrective deformations.

Exporting

Which skeleton do exported body animations target?

The exported skeleton is the body armature imported from the DNA, not the FK controls of the control rig. Import the FBX in Unreal Engine against that same MetaHuman body skeleton directly.

If the result looks off, double check which skeleton you selected in Unreal when importing the animation. If your animation is being applied to a body with different proportions use Unreal Engine's Retargetor.

Scene Setup

Should I change Blender's unit scale to match Unreal Engine?

No. Work at scene scale 1. The exporter reads the visual transforms and applies the Unreal Engine conversion itself.

Authoring at 100× to satisfy Blender's built-in FBX exporter leaves non-1 scale factors in the bind pose and breaks physics and other Blender features.