MEL 左右対称に複製（トランスフォームのフリーズとリセット）します。

FreezeTransformations;
performFreezeTransformations(0);
makeIdentity -apply true -t 1 -r 1 -s 1 -n 0;
ResetTransformations;
performResetTransformations(0);

duplicate -rr;

string $object;
string $objects= `ls -sl`;
for( $object in $objects )

{

setAttr ( $object + ".scaleX")-1;

};

FreezeTransformations;
performFreezeTransformations(0);
makeIdentity -apply true -t 1 -r 1 -s 1 -n 0;

string $object;
string $objects= `ls -sl`;
for( $object in $objects )

{

setAttr ( $object + ".opposite")0;

};

ReversePolygonNormals;