full bust adjustments – alternate methods discussion

(Note: this post is meant more as an open discussion, rather than a set tutorial since I’m experimenting with untested adjustments. So basically, all the following pictures and diagrams are for discussion purposes and have not be fully tested)

After yesterdays posts, there are a few more things I want to talk about with respect to bust adjustments. One of the glaring issues  (in my opinion) with the traditional Full Bust Adjustment (and Small Bust Adjustment) that we chatted about yesterday is the fact that these adjustments change the size of the waistline. The FBA will make the waistline larger, and the SBA will make the waistline smaller. Now the infuriating thing about that is that you will now need to adjust the waistline.

To be perfectly honest, these bust adjustments have always bothered me for this reason. But since I never need to do any adjustments for myself, I’ve never pursued the issue further – until today. I understand that theoretically the reason you need to keep the slash lines parallel is to maintain the grainline of the pattern and so you don’t mess with the shape and drape of the bodice – but it still doesn’t make sense to me that we increase the waistline and then need to alter it. So I wondered, what happens when you don’t keep the horizontal slash lines parallel, and instead pivot at the waistline, only increasing the dart?

Here’s what i did.

I started out by following the exact same methodology as detailed in yesterdays FBA post – except that this time instead of keeping the horizontal slash lines parallel, I pivoted at the waistline and allowed all of the ease to go into the dart:

My immediate thoughts are that that dart is freaking massive!! hehe. The Darling Ranges already starts off with a large dart, that increases in size for large sizes to somewhat accomodate for larger cup sizes – so this dart may be way too big. However, I do like the fact that it’s maintained the waistline, and at first glance the finished pattern doesn’t look too dissimilar to our final traditional FBA 


Then since I was testing some ideas out, I decided to also plot out a “quickie” adjustment I’ve often done in the past when I fit across more than one size. That is, cutting a different size for the bust and waist, and then blending at the seamline.

First thing I did was to make the dart by folding the pattern paper

I decided to use the example of and XL bust and M waistline – so drew a line between those points as my new side seam – then I cut along that line

Initial reaction? That’s a weird looking pattern. (Even weirder because halfway through I realised I should have done a size L bust and size S waist to keep all my examples consistent so i redid it – i’m sorry, please forgive this inconsistency!). From looking at it i wouldn’t think that would work – but truth be told, i’ve used this little quickie method for myself a number of times on other patterns with success. So I know in some circumstances it works – but whether it is best in this one is left to be seen.

Sooo after all that, I thought, let’s put all these adjustments on the computer and compare them. (I did my best to line up the front of the pattern and the necklines, since those are the parts of the pattern that don’t change, but my vector drawings aren’t perfect)

Interesting right? Here’s what I’m thinking – and I’d really love to hear what you all think too.

  1. Cutting 2 different sizes is clearly not accurate, since we’re not changing the size of the dart at all – so i’m gonna say that one is a no no
  2. As was noted before, the traditional FBA is resulting in a wider waistline – so we would need to take the pattern in at the waistline and redraw the seamline.
  3. Assuming we removed that excess in the waistline and redraw the seamline below the bust – the traditional FBA and my proposed FBA aren’t too different. I have to admit – I’m intrigued. Obviously the dart is larger in the alternate FBA, since the fullness from the waistline had to go somewhere else, and that somewhere else was the dart.
So now I’m left wondering whether this alternate version of an FBA is worth testing out. The thing is, is that extra 1/2″ that we’re seeing in the dart an issue? If it is, perhaps it’s better take the traditional approach and alter the waistline. To be honest, I don’t know right now!
And I guess that’s where I’m going to leave this post for now. I’m sure there are many many of you who have a lot of experience with having to do FBA’s – I’d really love to hear your thoughts on this issue.


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  1. says

    Hey! I really like your idea for the alternate FBA! If I could offer some improvement tips, it’s:

    1. With a fuller bust, you need to add more length to the bodice. A large curve takes more length that a small curve. If you leave the bodice length the same, an empire waist will bisect the bust and other nasty things can happen.

    2. Typically with an FBA, you extend the dart to the bust point (the fullest part of the bust, usually around the nipple) before you make the adjustment. This is because darts usually fall short of that point so as not to attract attention to the area. After the FBA is done, you can shorten the dart.

    3. The dart you made looks big, but often that large of a dart is what’s needed. Unfortunately, if you leave that large of a dart altogether it will usually sew up really funny or pointy. It’s better to split the dart up into more than one form of control, like gathers somewhere, or another dart in another place. Some people will sew two darts parallel to each other so each dart is only half as big.

    I hope that wasn’t too much information! I really like your adjustment and it would be great to see the original pattern overlayed with the FBA’s to see the difference! :)

    • MegMeg says

      Hannah! Thank you for the additional suggestions – i love them, and appreciate you taking the time!
      I think you’re right that spreading the dart is a good idea. I was thinking of splitting it between the waist and the side seam – but I like your idea of two parallel darts in the same seam much better – i think it would look quite pretty actually! You know like an additional detail :)
      With respect to the bust point, I know it’s really hard to see in the picture with the slash lines drawn, but rest assured I did extend the dart to the bust point before starting :) After the FBA the end dart point was the same distance from the original bust point as the original dart was (phew that was a mouthfull!) -I hope that makes sense!
      Thanks again for the additional suggestions – it’s really wonderful to hear ideas form someone who does FBA’s more often :)
      Oh and yes, i think you’re right – i should add an overlay of the original pattern! that would be very interesting!


  2. Siobhan says

    Thanks for the time & effort you’ve put into thinking this through. I’m often pondering ways to do an FBA without it looking too obvious. Perhaps this pattern would suit some of the dart being rotated to soft gathers or pleats at the shoulder.
    I also wonder whether cup size has all that much to do with bust adjustments – I’m a DD cup and shirts often strain or ride up, yet my measurements perfectly correspond to size S. Surely an FBA would make the bust measurent too big…maybe is something that calls for muslining!

  3. Majda says

    I like your blog :)

    I think with your second method you sholud try to blend below the dart, without folding, maybe with some curve? That way the dart won’t look so strange :)

  4. says

    This is the most useful (to me) FBA I’ve seen so far; thanks for this clear, posting!
    I’ll try and remember to send you the results after I’ve used it.