Closely isn't enough. For a morph to work the number of vertices must be exactely the same. Only if the pants were made FROM M3's mesh would the morphs PERHAPS be injectable. Perhaps becourse it also depends on how they are cut :o)

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.