Adding seam allowances to pattern block

pattern
Now that we have traced our pattern blocks it would be great to add seam allowances.

This is set within the pattern command. The first parameter that we are going to use is seam(x).

Simply add this line to the pattern block code that we have created in the previous lesson, for example:

pattern(
    name("Back skirt"),
    trace(BACK_WAIST_CENTER,BACK_WAIST_SIDE,BACK_SIDE_SKIRT,L,L2),
    fabric("Main"),
    qty(1, 1),
    seam(2),
    inc(TEXT_ZIPPER,TEXT_CENTER_BACK,BACK_HIP_MARK,ZIPPER_MARK,(r12,r2,r11))
)

As you can see, the seam allowance is set to 2 cm. You may use numbers or variables in this parameter, and I actually prefer variables, because it is likely that you will use the same seam allowances for all pattern blocks, or at least some sides of these. 

Let's create a variable for standard seam allowance:

sas=2.54*5/8 // standard seam allowance will be 5/8 inch

and use it in the pattern command:

pattern(
    name("Back skirt"),
    trace(BACK_WAIST_CENTER,BACK_WAIST_SIDE,BACK_SIDE_SKIRT,L,L2),
    fabric("Main"),
    qty(1, 1),
    seam(sas),
    extra((l,l2,sah),(ws2,l,sab)),
    inc(TEXT_ZIPPER,TEXT_CENTER_BACK,BACK_HIP_MARK,ZIPPER_MARK,(r12,r2,r11))
)

I click the Save and redraft button to see the changes. To see the pattern block better, I right-clicked it and dragged aside. You can see that the seam allowances have been added around the pattern block and they are the same everywhere.


Let us repeat the same for our front skirt: 

pattern(
    name("Front skirt"),
    trace(l1,l,FRONT_SIDE_SKIRT,FRONT_WAIST_SIDE,FRONT_WAIST_CENTER),
    fabric("Main"),
    seam(sas),
    qty(1, 0),
    fold(w1,l1),
    inc((v12,v2,v11),FRONT_HIP_MARK,TEXT_CENTER_FRONT)
)

Again seam allowances have been added around the pattern - but the center front line. This is because the center front is marked as the fold line, and the software was smart enough not to draw seam allowances there.


This is nice - but not good enough. I would like to add bigger seam allowances for the side seam to provide for fitting if required, and an even bigger seam allowance for the hem. I shall create two more variables for seam allowances - and I will place this code above the pattern commands, so that these variables already exist when they are used in patterns.

// seam allowances
sas=2.54*5/8 // standard seam allowance will be 5/8 inch
sab=2.54 // a bigger seam allowance for sides
sah=2.54*1.5 // seam allowance for hem

Now I want to change seam allowances for some edges of the pattern block, and leave standard seam allowances for all other edges. To do this I use the parameter extra. The syntax is as follows:

extra( (first point, second point, specific seam allowance), (first point, second point, specific seam allowance)  )

So each edge with specific seam allowance is described in its own brackets, and they are separated by commas. They are then all included into the brackets of extra parameter. The points are listed clockwise. 

For example, I want to use a bigger seam allowance for hem, which runs from point L to point L2. I can use a value in cm, or a variable, for example

extra( (L,L2,5) ) or extra( (L,L2,sah) ) - and I place the setting in brackets for the edge, and brackets for parameter, that is why the brackets are double here.

To specify a new seam allowance for the side seam, I need to redefine it from point WS2 to L2, and I'll set it to sab:

extra( (L,L2,sah), (WS2,L,sab )

The whole code is as follows:

pattern(
    name("Back skirt"),
    trace(BACK_WAIST_CENTER,BACK_WAIST_SIDE,BACK_SIDE_SKIRT,L,L2),
    fabric("Main"),
    qty(1, 1),
    seam(sas),
    extra((l,l2,sah),(ws2,l,sab)),
    inc(TEXT_ZIPPER,TEXT_CENTER_BACK,BACK_HIP_MARK,ZIPPER_MARK,(r12,r2,r11))
)

And the pattern block now looks as follows:


For the front skirt, the seam allowance for the hem runs from L1 to L, and the side seam allowance is from L to WS1:

pattern(
    name("Front skirt"),
    trace(l1,l,FRONT_SIDE_SKIRT,FRONT_WAIST_SIDE,FRONT_WAIST_CENTER),
    fabric("Main"),
    seam(sas),
    extra((l,ws1,sab),(l1,l,sah)),
    qty(1, 0),
    fold(w1,l1),
    inc((v12,v2,v11),FRONT_HIP_MARK,TEXT_CENTER_FRONT)
)


You may view your pattern blocks with or without seam allowances - the latter might be useful if you want to look closer at some details of your patterns and the seam allowances get in the way. To turn off seam allowances, click the button in the top left navigation. It will also turn off the grain line and the texts. 



To turn them on, click the button in top left navigation - 



Using the same buttons in print preview window you can export your pattern with or without seam allowances. The grain lines and the pattern blocks are always there in the exported files, as they are required there in any case.

Print preview with seam allowances:


Print preview without seam allowances:

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