I have a very simple question about Blender weight painting. How can I flip weight across the X axis? I am familiar with the weight painting setting that automatically puts weight on the opposite side as you paint, but I manually edited weight on one side using vertex groups on a more tedious part of the model and I now need to flip it to the other side.
Use the mirror modifier on your mesh. In edit mode, delete all of the right side vertices, then apply the mirror after you are done assigning weights.
This can be destructive, so always save a new blend file version before attempting this. Also, if you have shapekeys on your mesh, this will not work because you cannot apply modifiers to meshes with shapekeys. (This will also destroy the Basis Shapekey.) Another reason not to use this method is if you do not want a symmetrical mesh.
One last thing, make sure the mirror modifier is above the armature modifier.
Well, I have no idea what a shapekey is, and I do want it to be symmetrical, so I will try this. Thanks for the help.
It worked perfectly. Thank you for the help.