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LivingSoft Subscriber Newsletter | Volume 2

Pattern Drafting 101


How Sleeve Caps Work

The length of the sleeve cap curve depends on 3 separate and independant factors:
1. Cap width. Comes from bicep width plus ease, but can also vary somewhat based on bicep position and width of the base of the sleeve.
2. Cap height. Starts out just under actual armhole height, but is allowed to be reduced to armhole measurement. Actual armhole height varies by pattern type, and based on armhole ease.
3. Armscye length plus cap ease. Armscye length can vary based on armhole depth measurement, armhole design ease, user supplied armhole wear ease, actual back armhole depth (varies by Side Length), shoulder width, bust width, bust ease, across chest, and across back measurements. Whew. Long list. All of these can make the length of the armscye curve vary. Once you have the actual front and back armscye curve lengths, then we add cap ease to that.
Given these length, height, and width amounts, the program then drafts a sleeve cap. Let's assume that there are some values that just work and a cap is drafted. What happens now if that person's bicep measurement was wrong. They entered 10" when the actual bicep circumference was really 15". So, correct that wrong bicep measurement and we now must widen the base of the sleeve cap by 50%. What happens? Well, either we just lowered the cap height a lot. Or, we made that cap curve longer. A lot longer than the armscye curve now. That means we actually added cap ease. Not that we meant to. It just happened because the cap base got wider.
The same thing happens as any change is made that can effect cap width, height, or length. Change any of those and the balance changes. You may or may not be able to get the full list of height, width, and length (ease) settings that you want.
Try it. It may work. But, if you subtract cap ease, watch the cap height. It may get lower. You may not want that to happen. Or, if the cap is at it's lowest allowed value, then the actual cap ease will just not change, regardless of what you ask for.
It all has to balance, but it is very, very easy to come up with numbers that cannot balance in exactly the way you expected. The sleeve cap will fit the armscye. But, it may not have the ease amount you wanted. Or, it may not have the cap height you wanted. If you're lucky, you get everything you ask for. If you do not, then you just have to accept the fact that something had to compromise. Knowing why can help you, but getting everything you want may not be possible.
Here are a few of the less intuitive ways to get a taller sleeve cap:
1. Increase bust ease.
2. Reduce Across Chest or Across Back measurement
3. Add armhole depth ease
4. Reduce Side Length (makes back armscye taller)
5. Reduce bicep measurement or bicep ease
6. Increase High Bust measurement (armscye extends further outwards - longer curve - more fabric under the arm).