Drafting a Styling Curve and Alterations

Making your own curve stylist or French curve

A French curve is a set of curves made from varying sturdy materials that are used to draft the curves in patterns of different slopes. The French curve is also an invaluable  resource for altering patterns.


Unfortunately I don’t have a French curve but I was really wanting to adjust my husbands t shirt pattern last week so I had to find a way to make it work. It was actually so easy! JK I bought one after writing this! Haha

All I had to do was to trace the armscye curve of his pattern piece marking where the side seam point and the shoulder point on the curve. Then I cut the curve out and traced this it onto some craft paper so it was a little bit more sturdy.

You can see here I just put a piece of printer paper behind the pattern piece to start and then traced the armscye curve. Most tops have a different curve for the front and back so you’ll have to do this twice. After you’ve drawn the line make sure to mark the top and the bottom, that’s where you’ll line up the new armscyes and shoulder lines and you can cut your curve out!

Forward Thrusting Shoulder Line Adjustment

(The one I use)

I have noticed that the forward thrusting shoulder is probably the most common adjustment needed on people now in the 21st century. With the amount of looking down that everyone is doing at phones, computers or keyboards the shoulder tends to rotate forward. Shockingly I noticed the other day in one of my husbands rtw shirts that they had adjusted for the forward shoulder and the shoulder seam was an inch or two more forward than the center point of the sleeve!


What it is:

A forward thrusting shoulder is when your shoulder sits more forward than the rest of your body causing your shoulder seam line to feel like it is riding back. I have also noticed that this can manifest itself when your front delt is more developed than your back delt cough cough my husband haha. When your shoulder sits more forward it means your back sits wider and your chest is more narrow which leads to your less than ideal fitting garment.

What it looks like:

When this happens there is too much fabric in the front and not enough fabric across your back which can cause drag lines going across your upper shoulder and some pooling between your neck and shoulder. This is shown by having drag lines from the center out to the shoulder point. Luckily this is a super easy fix!


All you need to do is bring your shoulder seam of your front pattern piece down the designated amount and raise your back shoulder seam (making the armscye appear taller) that same amount! I started with 1/2 an inch and went from there but the rtw shirt that fits my husband perfectly for his muscular build is about an inch difference.

Step 1:

The first thing you’re going to want to do is measure down from the shoulder seam on the FRONT bodice the amount that your forward shoulder sits. I did one inch for Travis. 




Step 2:

When you add to one side of the bodice you have to do the same but opposite to the other to keep the pattern even! So you need to add the amount you used in step 1 to the back bodice here. 


Step 3:

Now using your styling curve or freehand you can ease in the neck curve to the new addition to the back bodice shoulder.



I really hope this helps,


Forward Thrusting Shoulder Point Adjustment

What it is:

This alteration is if just the shoulder bone sits more forward than the rest of your body or in the un-ideal place. Unlike in the forward shoulder line adjustment just the bone is sitting forward so the neck point is going to remain the same.

What it looks like:

This is shown with drag lines extending from the center front neck out towards the shoulder.


The first thing you’ll want to do is measure the amount you want to change down from the front bodice shoulder line, then connect the neck point to that new point with a straight line. Similar to what we did on the forward shoulder line adjustment but this time you’re only altering the outside point. This will have shortened the armscye of the front bodice so you’ll have to move the armscye down your designated amount just like to did in the forward shoulder line adjustment. Next we’ll move on to the back bodice, Since you shortened the front bodice shoulder you’re going to have to increase the height of the back bodice shoulder. You’ll do this the same way but opposite. Measure your designated amount up from the shoulder point and then connecting that point to the neck point. By connecting these two points you’ve created the new shoulder seam for the back bodice. You’ll then have to increase the height of the back bodice armscye just like we did in the forward shoulder line adjustment. 

By changing this you’ve also changed where the center point on the sleeve will hit. You’ll want to adjust your notch for the center sleeve. If you moved the shoulder point by 1/2 inch for instance you’ll want to move that notch forward 1/2 inch as well.

I hope to add photos to this too I just haven’t had the chance yet!

Sloped Shoulder Adjustment

What it is and what it looks like:

A sloped shoulder adjustment is really common and I had no idea about it until just a couple months ago! When your shoulders slope down from your neck out to the shoulder bone and the pattern isn’t altered for it, it causes drag lines that extend from the armpit up to the neckline. I have also noticed that overly big trap muscles can appear to cause this same thing and give the illusion of a sloped shoulder but it is really a higher neck base adjustment that you’ll need.


Good news is that this is a super easy fix! All you have to do is pinch out on the edge of the shoulder to see how much you need to adjust for your particular sloped shoulder to make the drag lines disappear.

Once you have that measurement, for us it was 1/2 inch, you’re going to lower the shoulder seam on the outside by that measurement and then connect the neck point to that new shoulder point.

In order to keep the armscye the same size you’re going to have to mirror this same alteration at the bottom of the armscye. Again for us we did 1/2 inch. So you mark 1/2 inch down from the armscye and use your French curve or a mirror of the curve your shirt has to create a new armscye that ends at that point.

You’re going to mirror these same adjustments on the back bodice as well and you’re good to go!

A sloped shoulder adjustment is commonly paired with forward thrusting adjustment and a rounded back adjustment so be sure to check those out.

Hope this was helpful!


I hope to add photos to this later today but I just haven’t had the chance yet!