Thanks for the response. So i checked that the center vertices are joined, and also not overlapping. All is good there. I imported the obj back into bodyslide and did a recalculate normals, and still have the noticeable seam issue: Do you think it could be due to the odd face/verticy pattern? I did a beauty fill to make sure there were no unsliced faces. This is what it looks like in blender: On a side note, I did increase the polygon count of the original mesh. (via manually cutting from vertex to vertex). Think the increase in vertex count did this? Edit3: Playing around a little more, when i hide texture in bodyslide, this happens: Which may just be a visual bug, since when rotated the center line comes back: Edit 4: The bottom rim and neck rim of shirt may have really close verticies. I did a shrinkrap at one point and the shirt rims became really close together. Would that effect that center line? Edit 5: Nvm about the Edit 4 comment. Removed those from mesh completely and tested, same thing still happens.