A very simple feature proposal.
Many riggers and mogrpah animators are usually coders however not all character animators are. And most of the time we make rigs ourselves. And while IF->FK is relatively simple to achieve the same can't be said for FK->IK.
There are known methods of doing matching its just they revolve around math and coding heavily. So why can't there be a tool that does that in a more graphical way taking out a burden of coding? Yes there is an addon in Blender that creates an autorig and has this feature but what about custom rigs?
- Click on a FK/IK Matching tool in Animation Tool Shelf
2 and 4) Press "FK/IK" field
3 and 5) Select all FK/IK bones in particular order and then press a button for to be remembered
- Press "elbows" field (for some characters there can be more than one)
- choose elbows tip of the bones for the IK arm and then press a button for to be remembered
- press "calculate"
- Under FKIK Matching tool 1 description and 2 button appear, buttons for matching IF->FK and FK->IK. And a description higher than buttons to distinguish what for this switch is. A user will be able to change the description to a meaningful one.
It can be an addon and not necessarily a hard coded feature.
While typing i also though you could create a slider for switching between FK and IK as well.
And while thinking further you could create an easy gui way for us to create and place buttons/sliders/etc and have a way to connect them to properties we're changing. But i guess this is a big separate feature.