Doing an FBA on a princess seam

Here’s a much needed guide if you like sewing patterns that have princess seams on the bust (which a fair amount of my patterns do!!) and you still need some extra space for the two watermelons 🍉 🍉

But first of you might think - well, is it even possible to do an FBA on a princess seam? … YES it absolutely IS possible! 

Remember that a princess seam is actually just standard dart manipulation. All you need to do is to slash open the side piece to find the "hidden" side bust dart and then you’re ready to do the FBA like we always do it (take a look at my other articles about the subject)!

Step 1:

Find the front bodice pieces

Step 2:

Transfer the (hidden) bust dart to the side piece by slashing b open, creating 1b and 2b and closing off the part of the princess seam that ends in the armhole.

Step 3:

While a and 2b is connected by the armhole, slide 2b away from piece a which causes 2b to tilt upwards while 1b shifts downwards. This opens up the side bust dart, aka makes it bigger. Decide on the new apex point and make sure to include the extra space created by the shift of 1b and 2b into the new bodice pieces (shown as dotted line)

Step 4:

Add the extra vertical length to piece a created by the shift downwards by 1b. And then don’t forget to close off the side bust dart again (connect 1b and 2b to just piece b), whereby we are back to having a princess seam.

I've added a pink colour to the drawing to show the extra ease created by the FBA so you can really see what difference it makes! 

Conclusion:

This guide can be used for any kind of princess seam. The key is always to find the "hidden" side bust dart and transfer it to the side seam and then it’s pretty straight forward from there!