Tutorial 30. Calculating Patterns for Cutting the Mesh Top.
I have printed out and glued together the initial patterns which I will use to cut the mesh fabric top. I have put them on the writing board for better clarity.
The pattern needs to be adjusted after the size of the already sewn dress. But, first of all, I need to measure the initial pattern itself. The best way to do it, as I said many times before, is to sew a mock-up and take all measurements off it. I know it for certain that not everyone likes sewing mock-ups. Many people try to measure the paper pattern, which results in lots of mistakes.
Please, let me explain how I take measurements off the initial pattern. You will be able to avoid the worst mistakes if you read into my explanations attentively.
A small foreword: the initial pattern was created based on several types of garments. I try to design interchangeable and combinable pattern pieces based on a children's construction kit principle. I want to be able to take back pieces from one pattern, for example, and front pieces from another pattern and combine them without any problems.
This was exactly how I made the initial pattern of the mesh top: the front pieces were taken from a strap dress pattern and the back pieces – from a shoulder seam dress pattern.
First of all, I compared the configurations of the side seam line of the side front piece of the strap dress and the side seam line of the side back piece of the corset-based dress with shoulder seams to avoid alignment errors.
And I noticed a small difference when I was doing that: the curve of the side front piece did not match the side seam line of the back piece. I put the side back piece on top of the side front piece, re-drew the back side seam line accordingly, and marked a new seam allowance line.
Speaking about seam allowances on my standard patterns: the side seams and the central back seam have a seam allowance of 2cm, while all other seam allowances are 1.2cm. Please note that all my patterns of corset-based garments include seam allowances!
After adjusting the configuration of the front side seam line, I draw the bust line, the under-bust line, the waistline, and the stomach line (7cm below the waist) between the notches of the pieces, and measure the distance from the waistline to the under-bust line on the side front piece.
The distance turns out to be 9.5cm, and the bride's Under-Bust to Waist measurement is 10cm. I accounted for this 10cm when cutting the base of the dress.
I mark 7.5cm and not 7cm down from the waistline to account for this difference of 0.5cm.
I have thereby evened out the distance from the under-bust line to the bottom edge of the mesh top on the pattern and on the assembled dress: it will be 7.5cm below waistline on the pattern and 7cm on the dress.
And now I will show you how to take measurements off the initial pattern.
Suppose I need to find Waist Width Front. I measure the distance between the seam allowance lines along the waistline of the side front piece. And then, taking the last measurement point on the measuring tape as zero, I measure the central front piece along the waistline, from the seam allowance line of the princess seam to the fold line. It is 40.5cm. I write it in the table. This method of taking measurements is more precise than putting together two parts of the same measurement taken separately off the side front piece and the central front piece.
You will see that some measurements are even more accurate, as much as to 5mm. In this particular case, high accuracy is demanded because I am sewing a garment to match a certain finished dress, the shape and size of which is not to be changed! If I were referring to someone's figure I could fix minor errors in measurements by shifting the seam lines, but this is not the case now.
I take all other relevant measurements off the front and the back of the initial pattern in just the same fashion and put them in the table.
Now let me do the necessary calculations and adjust the initial pattern to match the size of the assembled dress.
The table contains a list of measurements required for customizing the initial top pattern enclosed with the book.
- Bust Width Front,
- Under-Bust Width Front,
- Waist Width Front,
- Stomach Width Front (7 / 7.5). I took this measurement 7cm below the waistline on the dress and 7.5cm below the waistline on the pattern to even out the distance from the waistline to the under-bust line.
- Waist Width Back,
- Stomach Width Back (7 / 7.5),
- Bust Apex to Bust Apex,
- Clip: toward the neckline and toward the armscye.
- Side Neck Point to Bust Apex,
- Shoulder Tip to Bust Apex,
- Centre Length Back,
- Shoulder Tip to Centre Waist Back,
- Side Length,
- Under-Bust to Waist,
- Shoulder to Shoulder Across Back,
- Mid-Armhole Width Back,
- Shoulder to Shoulder Across Front,
- Mid-Armhole Width Front,
- Armscye Circumference.
Measurements taken off the finished dress are written in the first column of the table ("Dress").
Measurements taken off the standard pattern enclosed with the book are written in the second column ("Pattern").
You can see question marks in some lines of the Pattern column: for example, under “Side Neck Point to Bust Apex” and “Shoulder Tip to Bust Apex.” It is pointless to measure them on the pattern. I recommend marking them in their actual size right away, with seam allowances included.
It is impossible to measure Shoulder to Shoulder Across Front, Mid-Armhole Width Front, and Armscye Circumference on a flat pattern because its shape will be distorted after sewing the bust princess seam.
Let us start calculating.
Always look at Bust Apex to Bust Apex before proceeding to the main calculations.
Bust Apex to Bust Apex: my client’s measurement is 18cm and it is 20cm on the pattern.
18cm – 20cm = -2cm
This means that the central front piece of the dress pattern needs to be made 2cm smaller. Simply shift the pattern 1cm against the fold line of your fabric.
I write it down in column 3.
But if you shift the pattern against the fold line, you will automatically make it smaller along the full length. To keep this in mind, I write -1cm in all lines of the Bust Apex to Bust Apex column that refer to circumferences.
It is a very important adjustment so I always provide for a separate column for Bust Apex to Bust Apex.
After calculating adjustments to Bust Apex to Bust Apex, I need to define the configuration of the side seam line: first for the front and then for the back half of the garment.
All calculated values will be written in column 4 (Side Seam Front).
The configuration of the front side seam line is determined by two measurements: Bust Width Front and Under-Bust Width Front. Both are measured as distance between side seams across front.
Bust Width Front: my client’s measurement is 48cm and it is 50.5cm on the pattern.
Therefore, I need to shift the side seam line inwards at the under-bust line level to make the pattern smaller and arrive at my client's measurement.
But I have already adjusted it down by a total of 2cm by removing 1cm from either end of the bust line.
50.5cm – 2cm = 48.5cm
48cm – 48.5cm = -0.5cm
There is an excess of 0.5cm on the pattern which I will distribute between the two side seam lines of the front half of the dress. In other words, either front side seam line needs to be shifted 0.25cm inwards at the bust line level. I write -0.25cm in the table.
Under-Bust Width Front: my client’s measurement is 36cm and it is 41.5cm on the pattern.
I need to shift the side seam line inwards at the under-bust line level to make the pattern smaller.
But I have already removed 1cm from either end of the under-bust line, i.e. adjusted it down by a total of 2cm.
41.5cm – 2cm = 39.5cm
36cm – 39.5cm = -3.5cm
There is an excess of 3.5cm on the pattern which I need to divide between the two front side seam lines. In other words, either front side seam line needs to be shifted 1.75cm inwards at the under-bust level. I write -1.75cm in the table.
Waist Width Front: it is 37cm on the client and 40.5cm on the pattern.
In order to arrive at my client's measurement, I need to shift the side seam line inwards at the waistline level to make the pattern smaller.
I have already removed 1cm from either end of the waistline, i.e. adjusted it down by a total of 2cm.
40.5cm – 2cm = 38.5cm
37cm – 38.5cm = -1.5cm
There is an excess of 1.5cm on the pattern which I need to divide between the two front side seam lines. Either front side seam line needs to be shifted 75mm inwards at the waistline. I write -0.75cm in the table.
Stomach Width Front: my client’s measurement is 44cm and it is 47cm on the pattern.
I need to shift the side seam line of the pattern inwards at the stomach level to make the pattern smaller.
Again, I have already removed 1cm from each end of the stomach line, i.e. adjusted it down by a total of 2cm.
47cm – 2cm = 45cm
44cm – 45cm = -1cm
There is an excess of 1cm which needs to be distributed between the two front side seam lines. In other words, I need to remove 5mm from either end of the stomach line on the front half of the garment. I write -0.5cm in the table.
If I knew Shoulder to Shoulder Across Front and Mid-Armhole Width Front of the pattern, I would account for the narrowing of the central front piece, re-calculate the pattern, and put the resulting values in the table.
But I don't know these measurements at the moment.
Let’s look at the clip measurements.
Clip towards neckline: it is 6cm on the client and 11cm on the pattern.
6cm – 11cm= -5cm
I need to shorten the clip by 5cm.
Clip towards armscye: it is 11cm on the client and 13cm on the pattern.
11cm – 23cm = -2cm
Again, I need to shorten the clip by 2cm.
I write these values in column 4.
Things are now clear with the side seam line of the front.
Let us look at the side seam line of the back. All calculated values are to be recorded in column 5 (Side Seam Back).
Let us begin calculating. We will see what happens after I take into account all measurements and calculations from the table.
I need to adjust the position of the back side seam line in correspondence with Waist Width Back and Stomach Width Back.
Let us start from Waist Width Back: my client’s measurement is 32cm and it is 36cm on the pattern.
32cm – 36cm = -4cm
There is an excess of 4cm on the pattern, and I need to remove it using the two side seam lines of the back. In other words, I need to remove 2cm from either end of the waistline at the back of the garment. I write -2cm in the table.
Let us look at Stomach Width Back: it is 40cm on the client and 44cmon the pattern.
40cm – 44cm = -4cm
There is an excess of 4cm on the pattern, which I need to remove using the two side seam lines of the back, i.e. remove 2cm from either end of the stomach line. I write -2cm in the table.
The low back neckline makes it quite hard to determine how much the side seam line of the back needs to be shifted at the top. But the calculations show that I need to remove 2cm in the waist, as well as in the stomach.
I have decided to remove the same 2cm at the bust line level and the under-bust line level. I write -2cm in the table (column 4, lines 1 and 2) keeping in mind that they refer to the back circumferences.
Let us take a closer look at Shoulder to Shoulder Across Front and Shoulder to Shoulder Across Back.
Shoulder to Shoulder Across Back: it is 37cm on the client and 38cm on the pattern.
37cm – 38cm = -1cm
There is an excess of 1cm on the pattern, which I need to remove using the side seam lines of the back. In other words, I need to make the back 5mm smaller in the shoulders. I write -0.5cm in the table.
Mid-Armhole Width Back: my client’s measurement is 31cm and it is 37.5cm on the pattern.
31cm – 37.5cm = -6.5cm
There is, therefore, an excess of 6.5cm on the pattern and it needs to be distributed between the two side seam lines of the back. I need to radically change the width of the back by removing 3.2cm from either side. I write -3.2cm in the table.
Let us move to the length measurements.
Centre Length Back: the measurements coincide – 37cm on the client and 37cm on the pattern.
No changes needed here.
Shoulder Tip to Centre Waist Back: it is 40cm on the client and 41cm on the pattern.
40cm – 41cm = -1cm
It follows that I need to remove a total of 1cm. I write -0.5cm in the table.
Judging from my experience, it is best to mark all garment lengths, widths, and heights in their actual size when you are customizing a standard pattern.
And now, last but not least, let us look at Side Length: my client’s measurement is 18cm and it is 20cm on the pattern.
18cm – 20cm = -2cm
The pattern is 2cm longer than needed along the side. When I was re-calculating the initial pattern of the bodice, I mentioned that the biggest possible value you could remove at the top of the side seam line without shifting the waistline was 2cm. I write -2cm in columns 4 and 5.
These were all required calculations.
And now I want to show you several possible methods of drafting the back of the mesh top. You can either use patterns (which is what I have already done) or use the draping method (pinning fabric directly on the dress-form). You can even add a shoulder strap if you want.
I simply want to remind you how to do such things.
I will now draw the initial pattern of the back which was used for the base of the dress. I prolong the princess seam lines upwards keeping them perpendicular to the waistline. I often use an additional measurement – distance between shoulder straps. It is normally measured as bra strap to bra strap across back. A half of this measurement is usually between 8 and 9.5cm. I make it 19cm in most of my standard patterns (actual distance between seam allowances).
Distance between princess seams (aka Mid-Armhole Width Back) usually makes 19cm on my standard non-customized patterns when the garment is zipped up. It is a purely relative value.
In additional, I usually measure the distance between the two corners at the top of the back to which shoulder straps are supposed to attach. My client's measurement is 26cm.
These two measurements allow me to calculate the correct position of the corners at the back of the dress to which the shoulder strap will be sewn.
(26cm – 19cm) / 2 = 3.5cm.
Let me find the position of the top corner of the back.
I mark the calculated value (3.5cm) from the princess seam toward the side seam and draw a vertical line perpendicular to the waistline. All I need to do to find the precise position of the top corner is mark Top Corner Height from the waistline up along this vertical line. It is 24cm on my client.
I will sew a thin shoulder strap to this corner.
If you want to make wide shoulder straps, you will need to know Mid-Armhole Width Back. It is measured as distance between supposed armscyes across back. It is 31cm in my client's case.
I draw the armscye line.
(31cm – 19cm) / 2 = 6cm.
I mark the calculated value (6cm) from the princess seam toward the side seam and draw a vertical line perpendicular to the waistline.
You can usually draw this armscye line arbitrarily; it does not have to be too precise. Experienced professionals often have a natural feel of how to draw it.
I prolong the princess seam line and the armscye line – and here is a wide shoulder strap. The armscye line usually goes up to the shoulder and is basically vertical. You can double-check its position using Shoulder Tip to Side Waist and Shoulder Slope if necessary.
Now you know two ways of adding shoulder straps to the back of the garment: thin straps starting from raised corners at the top of the back or wide straps integrated in the armscyes.
You can put the side back piece next to the central back piece and draw a smooth transition line.
There is another very simple way of adding shoulder straps to the back pattern.
Simply prolong the armscye line, the princess seam line, and the central line up to the highest shoulder point (which is found based on your client's Centre Length Back measurement) and cut these back pieces out in full.
Then, sew a mock-up, put it on the dress-form or on your client, and cut the back neckline the way you want or the way the overall style implies. In our case, it will be a low back top.
We will go with the more traditional method: draft the mesh top by adjusting the initial pattern after the measurements of the assembled dress base.
But there is a faster way for someone who has enough experience in sewing corset garments.
You have at hand an adjusted pattern of the back half of the main bodice which you can simply polish up using the existing measurements.
In this case, you won't have to adjust the initial pattern of the back after new measurements.
But you will certainly need to calculate adjustments to the initial pattern of the front to build the front of the top.
It is easier for a beginner to cut away all excess from a ready pattern rather than add something to it.
Well now, all calculations are done, and I can adjust the initial pattern and turn it into a custom pattern with respect to all found values.