The Sloper
In garment sewing, you can buy many different patterns that are already made with a style to them, different necklines, different sleeve shapes, different lengths -- the sky is the limit where fashion is concerned. Once you've sewn for a while, a common pattern to have is a basic sloper, fitted to your own measurements that you can draw style lines on and manipulate into new patterns. A sloper in any garment sewing is a design sheet to make new designs on that will fit you because it's based on your fitted pattern. A quick google search will show millions of slopers for garments.
However, a search for the same in bras shows different bra patterns with design already in them or this sort of idea from early bras. (Source:https://www.pattern-making.com/draft-bra-pattern/)
The information for drafting modern bras has been something where you still have to pursue elusive drafting courses and scour the internet for information, and buy expensive text books on the subject. Even then, drafting books often say to draw a line at a certain measurement without explaining why you get that number, so if you want to draft for someone who is a 30A or someone who is a 40H, it doesn't really show you how to change that number.
Bra slopers function the same way as garment slopers and are based on your draft volume bra or your eve pattern. If you are lucky enough to fit into the Eve Classic pattern, you get to skip straight to the fun of sloper manipulation to make whatever seam lines you might be inspired by in Ready to Wear. If you do draft from scratch, the sloper is the light at the end of the tunnel to keep you persevering through to the end.
You might brainstorm on a sheet like this.
Then, when it comes time to make it in your size, this template is designed to skip the trial and error of drafting and skip straight to designing interesting new seamlines. The Bare Essentials Method walks through taking your fitted pattern and drawing in these template lines and removing the curves so you can place new style lines.
Obviously, this is a very flat representation of patterns that are very round. What is unique about this method of slopers is the Bare Essentials calculations for how much curve is added to the lines in each of these locations on the sloper star grid. The curves added in the drafting process are recalculated by mathematical formulas to get designs that fit without much tweaking. In all the calculations Jennifer has worked on to automate this process, she has even put together a calculator for the sloper that gives recommendations for your new designs when you put in the results from your volume test draft bra. Soon, she will be featuring a sloper class on her website.
The process of getting to a sloper takes a while, but once we have reached a fitting draft volume bra, we know the designs based on the sloper will magically fit, so subsequent bras are not starting over at the beginning.
