Couldn’t find any info about mirroring action constraints so was trying to figure out myself. So first thing I copied action constrains from one side to the other by using Copy constrain to selected bones option. Than I renamed target of that constrain from.L to. R. Than I went to the actions editor and created new empty action. Than I went to the action which contains keyframes of the left hand and used Key - copy keyframes. Then I went to the my new empty action which I prepared earlier for the right side hand and pasted keyframes. Then I started to rename manually all of them from.L to.R. And that’s it, here is a snag, because it doesn’t really allows to rename everything. So here I stopped and dont now what to do now. Please help.
You don’t really…
at least not once it’s in a contraint…
instead what you do is do your key frames while building the action constraint then…
use the the ‘copy pose’ icon (looks like a little clip board) on the bottom tool bar way over on the very far Right hand side…
then use the ‘paste pose’ icon… note there are two of these… one paste the exact pose to the same bone(s) your currently animating…
it’s Icon has an arrow poiniting down and to the Right…
then there is another Icon with the arrow pointing down and to the Left… (it also has a bit of a dotted line on the Right side also)
this Icon paste your pose across to the corresponding ‘mirror’ bone(s) you have set up…
now save that your Action constraints with the poses on both sides…
Remember you will only be using that action … within the constraint for that particular bone… so you can save a whole mess of individual bone key frames within just one action… but the action will only effect the bone the constraint is actually on