I’ve been struggling to get symmetry to work recently, and I’m not sure what I’m doing wrong… I feel like it used to just work “out of the box” on things like this PolySphere example, but now it seems really hit-or-miss… It does seem to work with files like “DemoHead” though.
I think you are just clicking the wrong button. You are activating the “Local Symmetry” button. “Local Symmetry” just enables symmetry to work on a per subtool basis where the subtool might not be lined up with the global axis. However, that still needs Symmetry to be active. I think the button you are looking for is the “Activate Symmetry” button in the Transform palette (see image) or you can just hit X on the keyboard to activate it… The reason it works on the DemoHead ztool is that symmetry was already turned on for that subtool when it was saved.
I’m not sure how I missed that, other than it being a LONG time since I’ve worked in Z-Brush.