I noticed this is Maya 2016 but it's present in Maya 2018 as well.
- Create a joint chain, make it IK.
- Parent a nurbs curve shape to the joints, the shape not the transform, to make FK controls out of the joints when IK is off.
- Create an object to drive the IK - now you have IK and FK controls.
- Connect an attribute to toggle fkik blending on/off and to also drive the visibility of the IK controls and inversely drive the visibility of the FK controls.
- The FK visibility toggling will be broken (FK shapes not visible despite incoming connection value being True, or visible when incoming connection is False). Unparent the effector from the joint chain and FK visibility will work.
- Tried this with multiple attribute types and multple approaches.
When Autodesk gets into the business of fixing bugs instead of introducing them, you might want to add this to the list.
