Upper Arm Mesh Issue: Long sleeve tops

hi! You have to select the mesh (or parts where you see the seams) by hovering each piece and pressing L to select that chunk of geometry in edit mode. Then "Remove doubles" to get rid of those seams.

You'll have to do this in each arm, and on skin body parts (neck and hands)



Every time you export a mesh from S4S (regardless of the type) you'll come across with this seams, so this step is a must each time you work with meshes.