Troubleshooting

The mesh tears at a joint

Almost always a marker in the wrong place rather than a weighting problem. Check that the shoulder, elbow, and knee markers are on the actual pivot and not on the surface in front of it.

If the markers are right and it still tears, the mesh probably has geometry the seam weld cannot merge, for example two separate shells overlapping at the joint.

Half the head stays behind when I turn it

Spine weight bleeding into the skull. RiggingCore runs a cleanup pass for this, but a Head marker placed on the crown instead of inside the skull will beat it. Move the marker into the middle of the head and regenerate.

A bone pokes through the skin

Usually the spine or a clavicle on a slim character. The fitter bends the spine and places the clavicles using Manny's own curve rather than a straight line between markers, and clamps it so bones stay inside, but a Spine Chest marker placed too far forward can still push a bone out. Move it back toward the centerline.

The fingers are a symmetric guess

MediaPipe did not find a hand and the plugin fell back to the oriented template. See Fingers for the reasons that happens and how to check.

The rig is not symmetric

You only place the left side, and the right is mirrored, so asymmetry means the mirror plane came out wrong. That usually happens when the character is not standing straight along the world axes. Straighten the source mesh and regenerate.

Generate Rig does nothing

Check that Source Mesh is set on the Rig Definition and that every required marker has been placed. The plugin will not build a partial skeleton.

The skeletal mesh saved but has no bones

CreateSkeletalMeshAsset needs a non-null USkeleton up front even though its header comment says otherwise. If you are calling the pipeline yourself, create an empty skeleton first, pass it in, and let MergeAllBonesToBoneTree build the bone tree from the finished mesh afterwards.