This handy script will Mirror Morph targets on the X axis. If you use Z-brush you can use it to quickly edit your base object in Max, mirror the changes and re-import the tool.Instructions for use:
1. Select a symmetrical model. (The model doesn’t need to be entirely symmetrical, only the parts you intend to mirror.)
2. Adjust the threshold or leave the default. I don’t recommend high numbers.
3. Hit the Initialize button and wait for it to process.
4. Once processed you may close the window. The data was saved to a temp file in your Windows temp directory.
5. When your ready, reopen the menu, select some verts that you modified, and hit the Mirror button and wait a few seconds.
6. With the same selected verts add a Morph modifier, make a reference to your base mesh, and this will let you set those back to the original position.
Fun isn’t it?