Mirroring morph targets using skin wrap
This tutorial uses the new skin wrap modifier in 3DS max 7 to enable the mirroring of morph targets. Ordinarily, if you sculpt a one sided target, raising the left side of the mouth into a smile for instance, and then mirror that shape you would expect it to give you a right sided smile target. Not so! In fact, the effect of blending the right smile to 100% will be exactly the same as blending the left smile to 100%.
To effectively make a mirrored morph target, mirror your left target naming it rightTarget and hide the left target. You should now have a mesh that looks correct (though it won't work as we've just found out).
Make a copy of your base mesh, making sure all the morpher targets are set to values of zero, and collapse it to an editable poly. Name it baseCopy_01 and Hide your base mesh
Add a morpher modifier to rightTarget and load baseCopy_01 into channel 1.
Crank it up to 100. This should blend your rightTarget mesh back so it looks identical to the baseCopy_01.
Now make a copy of baseCopy_01, name it baseCopy_02 and hide baseCopy_01. BaseCopy_02 will actually be the mirrored target.
Move to frame 10, turn on autokey and return rightTarget's morpher channel 1 to zero. Turn off Auto Key.
Make sure the two visible meshes are aligned to each other.
Return to frame 0 and add a skin wrap modifier to baseCopy_02 and pick rightTarget as a control object. Make sure the deformation engine is set to 'vertex deformation'.
Scrub the time slider. BaseCopy_02 should be pulled up into the right smile position as rightTarget's morpher channel blends from 100% at frame 0 to 0% at frame 10. You may have to tweak the falloff, influence and face limit settings (I set them to 0, 0, 1 respectively) to make baseCopy_02 follow rightTarget exactly.
Move to frame 10 and collapse baseCopy_02 to an editable poly.
Unhide your base mesh and load baseCopy_02 into an empty channel in the morpher modifier.
Change the percentage spinner and you should now have a fully functional right smile target to compliment your original left target.
This whole procedure should take you about 2 minutes once you get the hang of it - a massive time saving when you consider many morph targets take hours to sculpt! If you don't want perfectly symmetrical morph targets simply use this to quickly get you to a starting point from which you can begin to add asymmetry.
Hope this is helpful to someone - I know it's saved me a load of time.