Softimage Xsi: Smoothing between assembled patches

Dear all,


Once an assembled, single surface has been created from two surfaces there is still a noticeable interface. How can this be removed to show a smooth transition. (the two surfaces were boundary snapped before the creation of the single surface with only small shift in their respective positions)


I have adjusted settings in the SCM and this has helped, but the interface can still be seen, slight though it may be.


Any help would be appreciated.


Regards,

Alan.