Cups and their curves1 Patternmaking: Bra Cups

The thing about bras is that they’re very particular – the fit varies with almost everyone. Two women may be an A cup but the way the weight is distributed within that A cup is different. One women may carry the weight closer to CF while the other woman carries the weight closer to her side. One woman may protrude more while the other woman protrudes less. And that’s what I’m going to talk about today – projection.

Projection is needed for any 2-dimensional piece of fabric to fit the 3-dimensional human figure. Projection can be achieved through shirring, darts, or curved seams and in bra cups, it’s usually achieved through curved seams. If the curve of the cup is increased, the line becomes longer (a curved line is longer than a straight line) and there will be more projection. The same holds true for the opposite.

Projection almost always causes fitting errors with bras. When I sewed my first bra, using Pin-ups Girls Classic Bra, the bra band fit but the cups didn’t. I have small girls and the curves on my bra cups needed to be reduced, like major. As shown in the diagram above, I reduced the curve from bust point (usually at the halfway point of the curve) and tapered to 0″ at the sides.The lower cup of a bra is again, almost always more curved than the upper cup (think of the curve on a princess seam – the side front panel is more curved and eased into the CF panel, which is almost straight), so I reduced the curve on the lower cup more than I reduced the curve on the upper cup (3/4″ for lower cup – 3/16″ for the upper cup).

I reduced the curve to fit my less-than-endowed girls but if you’re girls are more endowed, increase the curve to increase projection and provide more room within the cup. Be sure to walk the two pattern pieces – lower cup and upper cup – after adjusting the curve. Like I wrote above, reducing or increasing the curve on any line will change its length. You want to make sure the two pattern pieces match up after the pattern alterations or as least maintain the same relationship (length of lower cup might be longer than length of upper cup because it has ease built into it).

The location of the curve can also be adjusted for women whose girls don’t sit in the center. If your girls sit closer to CF or sides, the shape of your cup pattern will be more curved where your fullness is – the curve on your pattern won’t be centered at the center of the pattern. Does this make sense?

Reducing the curve of the lower cup can also be used to “flatten” the appearance of your girls. Some women don’t like the Madonna, cone-breast look, and this correction will make the girls appear rounder and flatter instead of projectile.

Bras are particular, yes, but they’re not hard. Your girls will differ from the rest of the girls, I assure you, and that’s why I can’t stress enough how important a mock-up bra will be. Until you make a sample garment, you won’t know where to eliminate or increase the curve of your bra cup pattern.

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