Not sure what I am looking at in your file… Your file doesn’t have a complete right side arm, you kind of need that for it to work. Also, the 3d gizmo is disabled in pose mode, and I can’t figure out how to get it to work.
However, there was a mistake in the code in my example file that would cause it to not work on the right side IK to FK. So I went ahead and added in a right side to my example. This required more code work, which makes me see why this code might seem out of reach for most people… Hence why I see all the hacks for doing FK/IK snapping without code.
And let me address this right here and now:
I didn’t develop this code. I found it here: https://blenderartists.org/t/visual-transform-helper-functions-for-2-5/500965
The code posted there does all the work, all I did was write a couple more functions and operators to make use of the code. This is why I said:
All I’ve done is update this code to work in current versions of blender. To update the core functions (those in the above mentioned post) to current version of blender, I copied them from current rigify code.
I didn’t create this, I only know how to use it…
Randy