Typically, wrinkles will occur whenever there is 'force' on the clothing. Meaning, if someone is bending, the jointed areas, will have wrinkles appear. This is because the activity in this specific area will cause the fabric to crinkle up, becoming tightened and loose in that area. Remember, clothes are being 'worn' not 'glued' to the body. Whenever someone moves, the clothes will move with the body.
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