The portion of the back strap that I’m holding between my fingers is the amount that passes through the buttonhole.
The fabric I used for this dress was a thick cotton sateen (doubled up both ways because of self-fabric lining). My bow was also quite wide. The bulky amount of thick fabric that needed to wrap around the bow fabric on the outer side of the buttonhole meant that I needed to allow for 2-3 extra inches of length in the back strap. If I was using silk CDC (a thinner, lighter fabric), I could have shortened the strap.
And now for how the pattern pieces look, and how I created this design from a basic bodice sloper. In the picture below, I’ve overlapped the seams of a basic front and back bodice piece. This is what I started with.
I made the basic dress sloper up in a muslin first to see where I wanted the top of the bodice to reach to. I then drew up the new shape of the bodice. I found that I had to bring the sides in slightly for the new (strapless) design.
To work out how long the straps needed to be, I employed the use of some seriously scientific guesswork. I basically just did what you can see below. I measured from the shoulder strap to the middle of the buttonhole in a line that I imagined the straps would naturally be pulled into. As you can see from the pattern piece below (my first draft), I initially failed to take into account the portion of the strap that would extend past the buttonhole to wrap around the bow. I ended up lengthening this pattern piece by about 1.5″ for the final dress version.
And that is all there is to this design. It’s really very simple, but also so very cute. And I’m very confident that a certain person would have absolutely no problems in modifying a certain Two Fruits dress into a Mummy sized version.