Seam allowance

From Seamly

The seam allowance is the section of a pattern between the stitch line & the edge of the fabric. It also gives a bit of leeway for minor discrepancies from the expected shape; as such, garments rarely have a seam allowance of less than 1cm & all the mainstream pattern companies of the USA use 5/8" seam allowances on their patterns. A hundred years ago, two-inch seam allowances were not legendary. Quilters tend to use a seam allowance of 1/4" or 3/8" on the broad side.

Of course, since you are looking here, you probably already know what a seam allowance is, & you're just exasperating there waiting for instructions on how to put a seam allowance on your Seamly pattern piece. Don't worry, I will cease the extraneous blather here.

It is quite possible to include seam allowance in the basic drafting process, but, again, you probably wouldn't be looking here if that was your plan.

So there you are, pattern all drafted, pattern piece outlined with the Workpiece tool, wondering how you are supposed to add a seam allowance. Perhaps the fear that you are going to have to carefully cut at 5/8" away from your pattern piece is gnawing at your soul. Fear no longer! If you are wanting more than one width of seam allowance make sure that the points on either side of the part needing an odd allowance are selected as part of the workpiece before you continue.

Ready? Okay! Here's a picture highlighting the areas you will be working with.





















  1. You will notice the "Details" tab near the top of the screen, that's the tab you'll be working in. Click it if you haven't.
  2. Right-click the workpiece where you want to add a seam allowance. A short menu will pop up.
  3. Click "Options" at the top of the menu. The fully functional Workpiece tool dialog will appear.
  4. You are in the "Paths" section of the dialog. Click the "Seam allowance" tab along the top of the dialog.
  5. Use the checkbox at the top of this dialog labeled "Seam allowance" to turn seam allowances on. It's that easy.
  6. Feel free to change the "Width:" to whatever you prefer.

Be sure to save your file.

If you want some section(s) to have a different seam allowance keep that dialog open, (or save & reopen it. That would be good.)

  1. Observe the "Nodes" section of the dialog, about half way down. You will notice that there is a drop-down list labeled "Node"
  2. "Nodes" are what we're calling the points here. Select a node on one side of the section needing a different seam allowance.
  3. Assuming that you are working in the clockwise direction which was required to trace the workpiece, choose the point/node before the section needing a different seam allowance.
  4. Change the "After:" allowance to what the section needs to be.
  5. Select the point/node after the different section.
  6. Change the "Before:" allowance to what the section needs to be.
  • Repeat as needed

That's all for now! Please edit this as needed, or ask for help on the forum!