How to set bone driven controllers for corrective morph targets

I have modeled some morph targets to correct the deformation of the pelvis of a character. In the AnimBP I am trying to set up a bone driven controller so that if the leg rotates in a certain axis up to the 90 degrees it will set the value of that morph target, mapped from 0 to 0 degrees and 1 to 90 degrees.

The problem is that I don’t understand how to set the parameters correctly for this node and can’t find any sources on how to properly achieve this. Could I get some help with this?

Take a look at a Metahuman Maya rig and in UE4 look at the Metahuman Post Process AnimBP, and you’ll see the Pose Driver node used all over the place.
In your case you need to create an animation in Maya with a set of poses which will trigger the corrective shape, then using the pose driver you can link the correctives…is not simple to setup, but read the documentation to see how to use the Pose Driver node.

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Sorry, I suppose I should have mentioned this then but I use Bender and the AnimBP in Unreal Engine is used to control the rig with live mocap.

Yep, the Metahuman setup is still helpfull in this case, since it uses control rig and the post process animBP is taking care or handling corrective shapes, but for Metahumans the correctives are driving joints via skinning, while in your case you’re using morph target which will be triggered by a set of poses that you’ll feed into the Pose Drive node.
If you’re doing live mocap, the post process animBP is always active and once set, it will work indipendently from the main AnimBP.

I won’t be able to use a control rig though because of the live mocap workflow that I am on.
That being said I am new to this, could you explain why I should use a Pose Driver instead of a Bone Driven controller?

As far as I know, bone driven controller is used to copy a rotation from one joint to another, while the Pose Driver act as a kind of “Set Driven Key” ( driver in Blender ), but instead of working on just one axis, it works by doing interpolation between xyz, so that if two axis are active at the same time, the Pose Driver interpolates the value of each corrective pose accordingly.
This node is based on the RBF plugin by Hans Godard, Epic made their own version to wotk inside Unreal.

Bone drive node works as well