In bone edit mode, How can i mirror bones properties ?

Such as roll, envelope,radius and head and tail transformation properties .

I know you can use X-mirror to begin with, but let’s say something messed up in the middle after the whole armature is already set, how can i mirror those settings in the X axis ?

X-mirror will mirror all of those properties you list, as long as the bones have corresponding names across left and right (hambone.L and hambone.R for instance. OR spleenbone_L and spleenbone_R would also work. .L or _L are the two naming conventions that mirror properly). It won’t mirror bone constraints though. For that reason I usually just make the left and center, then copy and mirror the left side when it’s complete.

Thanks, but this solution is good only when you are building the armature, not on already made bones :S

What do you mean? You can still change an existing armature in Edit Mode, and X-Axis Mirror works the same way whether you just created the bones two seconds ago or three years ago.

Let’s say all the armature is done and functioning and animated and rigged and everything . and all of a sudden something got fucked or i didn’t noticed it at the beginning and some of the bones values like roll etc… got changed in one side of the armature, how can i mirror those settings so they will be symmetrized ?

Do you have bones that are rolled differently on one side of the armature from the other, even with x-mirror on? If the rolls have changed suddenly, it’s most likely the result of a mistake made with a constraint. The way to fix that is to fix the constraint, not the bone rolls. Are the bone rolls different in both Edit mode and Pose mode? If that’s the case, then it’s not the result of a constraint. The quickest way to symmetrize something like that is to turn off X-mirror, fix the messed up side, then turn X-mirror back on. Select the side you just fixed, everything you changed, then hit G, then right click to cancel. Hitting G will still mirror the current setup without actually moving anything since you cancelled the move.