when a single piece of clothing that is supposed to be one thing in real life is neatly stitched (welded) together, there is no reason to do any export - import - obj - whatever process. It should just work. If it doesn't, the thing contains flaws in the obj structure: misplaced vertices, missing edges, whatever. Some dresses for instance actually exist of various seperate parts with no common verts or edges connecting them. The parts are just intersecting geometrically, but they make not one singular mesh. But because all those parts conform neatly, you will never notice. Until you throw them into cloth room. Then they'll fall apart.

When the parts have some vertices in about the same positions, welding might do the repair job. Sometimes you need all the tricks you can think of. Sometimes you have to reconstruct the obj in a 3D mesh editor. There is no single treatment for all issues. You might need to pick the mesh apart to see what's wrong. generally, the parts were not stitched together.

But again, if the mesh is good, then a conforming piece can get clothified without any further process.

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Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.

visit www.aRtBeeWeb.nl (works) or Missing Manuals (tutorials & reviews) - both need an update though