Developing a custom pattern. Part one.

In my line of work it’s pretty normal – a client brings me a sewing pattern with the design she is after, but because she wants some heavy modifications done (or the pattern can not accommodate her figure) the pattern itself can not be used.

To be honest, even if the pattern was usable, I’d still prefer drafting my own. I like having the full control of the ease and, ultimately, the fit of the garment. I also like taking the full credit when the fit is awesome (hehe).

So I thought, why not share my process? Maybe It might be of some interest to you?

And so, this time I have to work with Simplicity 2550 design.

Simplicity 2550

My objective is to make a dress like the red one, but with a scoop neckline, sleeveless and fully lined. This is how I make this happen.

Step 1 – Illustration.

I draw the design I am working on. This is important because a visual of what I am trying to achieve helps me stay focused while deep in the process of pattern making.

I think the dress should look something like this.

Sleevless dress

Step 2 – Commercial pattern analysis.

This is another very important step, because that’s how I find out the fit of the pattern and the location of the decorative elements I need to copy.

First, I compare the client’s measurements to the pattern’s size chart and find the most appropriate size. I don’t get stuck on exact numbers though, because of the extra generous ease these patterns are famous for, I have a “wiggle room” on all measurements.


As you can see, I chose size 18, although my client is a bit larger at the bust, waist and smaller at the hips.

Sadly, the pattern only provides finished measurement at the bust, all others you have to work out yourself, using your measuring tape and some detective skills.

The detective skills come very handy because the pattern does not mark the hip level, even with a notch. However, in their measurements chart they suggest you measure your hips 9” below your waist, so It is safe to assume that the hip line will be found 9” below the marked waist line on the pattern. Elementary, Watson.

At this point you might be wondering why can’t I just chop off the sleeves and make a sleeveless dress?

The reason is the fit. A bodice with sleeves should have more ease in general, and especially across the back. I am also sure that this bodice will gape at the back armscye and quite possibly in the front too, because the shoulder and bust darts are usually on the small side. Since I am not sewing a muslin, there is a little margin for error, so I’d rather be safe.

Step 3 –  Design evaluation.

One of the main features of this design is the raised waistline and the vertical parallel darts/pleats in front. These will have to be copied exactly. I measured the pattern and found out that the waistline was raised by 9 cm, the darts are 3.5 cm apart and about 8 cm away from the centre front.

There is also a zip, a dart and a vent at the back, and the fullness was added to the front skirt only. Easy!

Step 4 – Ease selection.

The ease selection is a bit of an art, because there are so many factors you have to keep in mind. On top of the usual ones, such as fabric type and fit, there is your client’s preferences and your own decisions, based on what you think will flatter the client’s figure.

I’ll start with 4 cm at the bust, knowing that the fabric is quite heavy for the dress, so it needs less ease. I’ll also give her 4 cm ease at the waist to keep that semi-fit going and 4 cm at the hips, knowing that I’ll be developing the skirt block, so I don’t need la lot of ease to start with.

As you can see it is quite different from what the pattern has built in – the waist ease of 12 cm is absolutely monstrous. Unless you really don’t want to show your figure (and my client has a lovely shape, why on earth would you hide it?), even 6 cm ease at the waist would be a lot.

Step 5 – Design development


After the chosen ease was added to the block, the design development begins.

First, I adjust the neckline – I lower and widen it as agreed with my client. Just in case, I’ll add wide seam allowances here for a possible change of mind.

pattern development 1

Then I mark the raised waist seam position and cut the block along this line.

I remove the shoulder dart because my client has pretty good posture, plus it is a sleeveless dress, so I can get away with it. Then I transfer the bust dart into the waist seam and split it in two, making sure the distance between the darts and their length is the same as in the commercial pattern.

Pattern development2

After this I remove 0.5 cm from the armscyes and necklines to prevent gaping – a very common thing on cut away necklines. Then, I clean up the draft and remove all the unnecessary lines.

Pattern development3



The skirt pleats must match the bodice darts exactly, so I move the skirt dart to match the right bodice dart. Then I mark the position of the second pleat on the skirt, slash at the marked lines and spread the skirt until the correct pleat widths are achieved.

Pattern development4

At the back things are much simpler. All I need to do is add the vent and mark the length of the back zip.

Pattern development5

The seam allowances and hems are added and the pattern is ready for cutting. I added 2 cm seam allowances for possible alterations.

Patern development6

For now, the pattern work is done and there is lots of sewing ahead! :)

Lena Merrin
Lena Merrin

A dressmaker of many years, I enjoy drafting patterns and create custom garments.

11 thoughts on “Developing a custom pattern. Part one.

  1. Janelle Khawly says:

    I left a comment here yesterday but it is still not showing so not sure what I did wrong, there is some wierd with my phone lately. Anyhow, just wanted to say great post and also ask when you remove the 0.5 from the armscye and neckline does that just get rotated into the dart by slashing and overlapping or do you do it another way?

  2. Louise Gilbert says:

    Thanks for that, I love seeing how to manipulate a block pattern, thats the whole point of making one but sometimes I need a bit of a visual to show me how!

  3. Roberta Fahrni says:

    Great post! I love learning this! Looking forward to the next installment. Thank you!

  4. Janelle Khawly says:

    Fascinating Lena, these kinds of posts are my favourite. Couple of questions…. When you say you remove 0.5 ease from neckline and armscye do you mean taking out a small wedge via a cut and slash overlap (I can’t think of a better term, I hope that makes sense) which gets transferred into the darts, or do you do it another way. Also, what program do you use for your pattern work. Is it illustrator or something more industry specific.

    • Lena Merrin
      Lena Merrin says:

      Hi Janelle, I just discovered that you comments were caught in a spam filter. Yes, I do exactly what you said – overlap to remove a small wedgie. And I use illustrator to draft the patterns, I’m quite a fan!

  5. Stitcheuse says:

    Wow! Thank you so much for this walkthrough! Explain the process – ‘detective work’ – and fitting choices is so invaluable!

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