The name is a little unstable and may change in the future. Some people like to call this part Increments, while others seem to prefer Variables. I’m not too sure which name I’d prefer, since this is also the place where all the length, angle, curve details are displayed in case you would like to view one of them. However, the only item that I really, really use is the Custom Variables.
I prefer to think of this as extra measurements and formulas that are exclusive to the pattern and not the person, since we already have all the person’s measurements that we need, in the measurements file. EASE So what do I consider ‘Exclusive to the Pattern’? Ease is one of them. You can draft a bodice and convert it to a blouse which is normally worn against the skin. But you will still need to add a few centimeters of ease to various areas so that the person can move in the blouse. You could do this in the pattern itself while drafting but what if you’d like to convert this bodice pattern to a coat? The ease will be more because one would normally wear a blouse under the coat and still need to move around in it. If this happens, you will need to go through all the nodes to find where the ease was added to the formula. However, if you had an item in the variables for ease, you could just edit this value and all the formulas would adjust themselves accordingly. And then, you may want to make a crop top, which is worn against the skin, out of fabric that will stretch quite considerably. In this case, you will be working with a negative ease. Once again, you will only need to edit the ease to a negative value and the resizing of the pattern will automatically adjust. FORMULAS If you have read any of my previous posts, you will know that I love drafting with a multisize measurement file attached. I also like to draft my patterns to resize correctly when I change the size, which brings me to pattern-specific formulas and the reason why I like to include a Size code in all of my measurement files… To set the stage, I’m merrily drafting away at a bodice from Winifred Aldrich’s book, Metric Pattern Cutting for Women, when I reach the point where I need to create the armhole curve and I get thrown a curve ball… Right at the end of drafting the back, I am presented with the instruction to: Draw armscye as shown in diagram touching points 16, 13, 25, 23, 21; measurement of the curves: From 12 from 22 sizes 6–8 2.5 cm (3 cm) 2 cm (2.5 cm) sizes 10–14 2.75 cm (3.25 cm) 2.25 cm (2.75 cm) sizes 16–20 3.25 cm (3.75 cm) 2.75 cm (3.25 cm) sizes 22–26 3.75 cm (4.35 cm) 3.25 cm (3.75 cm) I can remember the 1st time I did this. It was in 2017 and I had to read the instruction very carefully... TWICE. Eventually, I decided that, since I was following the pattern and the pattern instructions are for a size 12, I need to create a node in this position for the ‘sizes 10-14’, and draw the curve to touch this node. Well, my armhole was really beautiful and I was so thrilled. Whoopee!! ... Until I loaded up a size 24 measurements file. The armhole was almost square and I could’ve cried. This is where the increments/variables come into play with a very fancy ‘If, then, else’ formula. So… if the size is less than 8, then 2.5cm, else if the size is from 10 to 14, then 2.75cm, else if… And the way to do this in Seamly2D is like this: size>20?3.75:size>14?3.25:size>8?2.75:2.5 To break it down, what I’m saying is that… if the size is larger than 20, then it will be 3.75cm, if this size isn’t larger than 20, but larger than 14, then it will be 3.25cm, if the size is neither larger than 20 nor larger than 14, but it is larger than 8, then it will be 2.75cm, and if it isn’t larger than any of these (so anything under size 10), then use 2.5cm. I’m sure that you will admit that to figure this formula over and over for each pattern that you make will be time consuming, confusing and tedious. I just find it much easier to set it up in one pattern and copy and paste it to the next pattern so that it’s available when & if I need it. The symbol of ‘Then’ is ‘?’ (question mark) and the symbol for ‘Else’ is ‘:’ (colon). Then there’s the ‘Size_Scale’ where the pattern calls for and amount to be added to a length according to the size scale. For example… 15cm and add 1cm for each size above or deduct 1cm for each size below, size 12. If I have an item in the Variables called ‘Size_Scale’ with the formula: (size-12)/2, then I can use the formula as follows: 15+(Size_Scale * 1) This way, if the size is size 12, then it won’t add anything to the 15cm. However, if the size is a 6, then it will add -3 to the 15cm and return 13cm or if the size is 20, then it will add 4cm to the 15cm and return 19cm. To use these 'size' formulas, you need to have a 'size' code in the measurements file and they work for both individual or multisize measurement files, which is nice - you can switch between them at will and the formulas will remain constant. These are examples of how I use this part of the program and I hope that you can use it to make your drafting experience easier, too. Comments are closed.
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AuthorMy name is Grace and I love all things that fall under the title "Hobby" MENU
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February 2021
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