An Example
I’m going to use Knitty’s Festive cardigan as an example. Cardigans are a particularly good candidate for modifying the positioning of shaping. In a regular sweater, there’s a lot of stretch all over which can compensate for a lack of good, targeted shaping. In a cardigan, horizontal stretch results in the dreaded button-gaping that we all hate. Clever positioning of shaping can help to minimize horizontal stretch by making sure the fabric needed to cover your curves is optimally positioned before you even put the cardigan on.
These instructions are written for a bottom-up cardigan, but can be adapted for any garment that already has shaping.
The Difference Between Princess Seams and Darts

Princess seams travel all the way up the garment, and can occur on either front or back or both. If you use princess seams, you’ll have two seams on each side of the garment, no more or less. If your garment doesn’t have shaping on every other row, you can continue the appearance of the princess seams by slipping a stitch every other row so as to keep your elegant line. Increases can also make keeping the princess seam line a challenge– I recommend slipping a stitch every other row, as usual, and increasing on the inside of that stitch.
Darts only occur where the shaping needs to happen, and so blend more easily into the overall fabric of the garment. You can use as many darts as you feel are necessary– two or more are customary for each bust point, and two for the bum shaping. This is because the bust is actually made up of two bust points surrounded by less highly raised areas, and so the bust darts need to happen to highlight each point. On the other hand, the bum has only one highly raised area, and so only one point needs to be highlighted.
First Step
Choose a cardigan and determine the size you want to knit. This will be the same sizes you would normally knit, since we’re not changing the dimensions of the cardigan, just the shape.
The ideal cardigan or sweater for this technique does not have a unique front or back motif (such as is found in Bristow in Knitty) that would get in the way of your shaping. Overall motifs are usually fine, though the way darts cause the fabric to bias will be more apparent in an all-over pattern motif than in stockinette. Princess seams will be apparent no matter what you do, as they’re intended to be a design feature as well as a shaping tool.
I’m using Festive, a stockinette cardigan with seed stitch edging, worked from the bottom-up. Front and two back pieces are worked separately. For the sake of generating some numbers, I’ve chosen to hypothetically knit the 40″ bust size.
Second Step
Decide what look you’re going for. You can either use darts, which are positioned only where you need them, or princess seams, which run up and down the garment on front and back in a continuous line. Princess seams are generally considered more elegant, which may or may not fit the garment you are modifying. Darts are subtler. For images of garments with princess seams, check out this PDF from Sewing.org.
If you decide to use darts, you will need to take two additional measurements– measure your underbust (the circumference of your ribcage under your bust) and the circumference of your waist at the narrowest point.
Underbust measurement: 33″
Waist measurement: 30″
If you decide to use princess seams, you don’t need to do any measuring beyond what you already did to choose your pattern size.
Third Step
Determine where to place your darts or princess seams. Again, Knitting Daily has a great tutorial on how to place bust darts. You’ll have two bust darts on each side of the cardigan, but only one princess seam. Position the princess seam approximately where the black clip is in the Knitting Daily photos, so that it falls approximately on or a little to the outside of the center of each bust point.
When placing back darts, use the same Knitting Daily logic. Wear a loose t-shirt and use clips to gather the fabric so that it shows off your curves best. The place where the clips should be will also be where your darts go. You’ll just need two darts for back shaping. Whether you choose to use princess seams or darts, the back shaping will occur in the same place.
Where I’d put my princess seams: 4 inches (20 sts) in on each side of the back and front.
Where I’d put my darts:
Bum darts: 4 inches (20 sts) in on each side of the back and front.
Bust darts: 2 inches (10 sts) and 4 inches (20 sts) in on each side of the back and front. (2 darts per bust point)
Fourth Step
Princess Seams: Once you’ve decided where to place your shaping, and what kind of shaping you want to use, start knitting the garment! Princess seams usually stretch from the bottom hem (or very close to it) to a little over or under the tip of the bust. For a princess seam, merely do the exact same shaping you are asked to do by the pattern, only instead of doing the shaping two stitches from edges of the piece, you’ll do it closer to the middle of each side, in the location you’ve pre-determined will best highlight your curves. On stretches without decreases or increases, remember to slip stitches to create the continuous line of the princess seam.
Darts: Once you’ve decided where to place your shaping, and what kind of a shaping you want to use, start knitting the garment! Bum shaping will occur like princess seam shaping– just shift the required pattern shaping over a few inches on each side. Bust shaping is more complex; this is where your waist and underbust measurements come in.
You will want to follow the pattern’s shaping instructions for the bust up to a point. Subtract your underbust measurement from your waist measurement to get a number we’ll call W. If W is 0, then you don’t need to do any waist shaping before the bust shaping, and you can skip ahead to the next paragraph. If W is greater than 0, then you will need to do your bust increases as the pattern dictates until you have increased W inches OR until you have worked half of the total bust shaping rows in the pattern.
W = 33 – 30 = 3″
3″ of increases = 15 sts of increases TOTAL, or approximately 8 stitches of shaping on each side. In the Festive pattern, this will take 32 rows to accomplish, less than 1/2 of the total rows used during the pattern-provided bust shaping.
After you have achieved the circumference of your underbust plus pattern ease (or worked half the bust shaping increase rows), you can start thinking about darts and bust shaping. In order to do the bust shaping, find out how many unworked rows of bust shaping the pattern calls for– we’ll call it X. X will be the total number of rows of bust shaping called for by the pattern minus the number of bust shaping rows you have already worked (if any) to increase the W inches described in the last paragraph. Then decide how many bust darts you’ll need for each bust point– Y. X/Y = Z, the number of rows to use in your dart shaping. Darts should begin very close to where your underbust swells to become your bust– probably about half of the way through the pattern’s bust shaping.
X = # of bust shaping rows in pattern (here it is unclear, but I’ll estimate 64) – rows already worked (32) = 32
Y= 2 darts per bust point
Z = 32/2 = 16 rows for dart shaping
If you haven’t already worked 1/2 of the bust shaping rows, work those rows now, but without any shaping– follow any instructions for motifs, but don’t do any increasing. Then begin your dart shaping, following the rate of increases called for in the pattern (inc 1 st per side every 6 rows, for example) but doing those increases for each dart rather than each side. If you have two darts per bust point, then you’ll be doubling the rate of increase compared to the pattern shaping. If you have three darts per bust point, you’ll be tripling the rate of increase, and so on. Once you have knit Z rows, stop– you’ve accomplished your darts! Knit straight until you reach the armscye shaping, then follow the pattern directions for the rest of the knit.
Congratulations! You’ve shaped your knitted sweater for your personal, three-dimensional bodily shape.