xsi = Application

selected = xsi.Selection
sourceMesh = xsi.PickObject("Pick source (enveloped) mesh", "Pick source (enveloped) mesh")("PickedElement")

if sourceMesh:
    freezeMe = []
    for targetMesh in selected:
        if targetMesh.Envelopes.Count > 0:
            xsi.RemoveFlexEnv(targetMesh)

        gatorOp = xsi.ApplyGenOp("Gator", "", targetMesh.FullName+";"+sourceMesh.FullName, 3, "siPersistentOperation", "siKeepGenOpInputs")(0)

        srcEnv = sourceMesh.Envelopes(0)
        srcEnvProp = (p.Target2 for p in srcEnv.InputPorts if p.Target2.Type == "envweights").next()

        env = xsi.TransferClusterPropertiesAcrossGenOp(targetMesh.FullName+"."+targetMesh.Type+".TransferAttributes", targetMesh, srcEnvProp, "Envelope_Weights")
        freezeMe.append(gatorOp)

    xsi.FreezeObj(freezeMe)
    xsi.LogMessage("Gatored %s's envelope to   --->   %s" % (sourceMesh.FullName, selected.GetAsText()), 4)

# TODO:
# Middleclick for continuous picking, left click for single.
# Offer to purge unused deformers