Hi Ced, on a surface use the MultiIso plug-in:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6841.1
or get the upgraded one from Max's plug-in file archive page:
http://moi.maxsm.net/media/files/

For between 2 curve use Max's cMorph plug-in:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6373.1

- Michael