- Tutorials
- Pattern design tutorial
- Part 2: Parametric design
- Completing the neck opening

# Completing the neck opening

We’ve constructed the perfectly sized quarter neck, and we’re going to use this to create our complete neck path by flipping and mirroring it.

## Hiding our quarter neck opening

To make our code easier to understand, we’re going to leave the `quarterNeck`

path
as it is, and simply chose to not show it.

To accomplish this, we’ll call the `hide()`

method on our path:

```
function draftBib({
Path,
Point,
paths,
points,
measurements,
options,
part,
}
) {
/*
* Construct the quarter neck opening
*/
const target = (measurements.head * options.neckRatio) /4
let tweak = 1
let delta
do {
points.right = new Point(
tweak * measurements.head / 10,
0
)
points.bottom = new Point(
0,
tweak * measurements.head / 12
)
points.rightCp1 = points.right.shift(
90,
points.bottom.dy(points.right) / 2
)
points.bottomCp2 = points.bottom.shift(
0,
points.bottom.dx(points.right) / 2
)
paths.quarterNeck = new Path()
.move(points.right)
.curve(
points.rightCp1,
points.bottomCp2,
points.bottom )
``` .hide()
delta = paths.quarterNeck.length() - target
if (delta > 0) tweak = tweak * 0.99
else tweak = tweak * 1.02
} while (Math.abs(delta) > 1)
return part
}

We’re saying: *hide this path*. In other words, don’t show it.
The path is still known, and we can still use it to calculate the length of the neck opening.
But it won’t show up on screen or on the page.

## Create the complete neck opening

Now that we’ve hidden our homework, let’s create the complete neck path. As the neck opening is symmetrical, there’s no need to re-calculate the points on the other side. We can just flip them over, so to speak. And that’s exactly what we’ll do.

Let’s add some more points, and then construct the complete path for the neck opening.

```
function draftBib({
Path,
Point,
paths,
points,
measurements,
options,
part,
}
) {
/*
* Construct the quarter neck opening
*/
const target = (measurements.head * options.neckRatio) /4
let tweak = 1
let delta
do {
points.right = new Point(tweak * measurements.head / 10, 0)
points.bottom = new Point(0, tweak * measurements.head / 12)
points.rightCp1 = points.right.shift( 90, points.bottom.dy(points.right) / 2)
points.bottomCp2 = points.bottom.shift( 0, points.bottom.dx(points.right) / 2)
paths.quarterNeck = new Path()
.move(points.right)
.curve(points.rightCp1, points.bottomCp2, points.bottom)
.hide()
delta = paths.quarterNeck.length() - target
if (delta > 0) tweak = tweak * 0.99
else tweak = tweak * 1.02
} while (Math.abs(delta) > 1)
``` /*
* Construct the complete neck opening
*/
points.rightCp2 = points.rightCp1.flipY()
points.bottomCp1 = points.bottomCp2.flipX()
points.left = points.right.flipX()
points.leftCp1 = points.rightCp2.flipX()
points.leftCp2 = points.rightCp1.flipX()
points.top = points.bottom.flipY()
points.topCp1 = points.bottomCp2.flipY()
points.topCp2 = points.bottomCp1.flipY()
paths.neck = new Path()
.move(points.top)
.curve(points.topCp2, points.leftCp1, points.left)
.curve(points.leftCp2, points.bottomCp1, points.bottom)
.curve(points.bottomCp2, points.rightCp1, points.right)
.curve(points.rightCp2, points.topCp1, points.top)
.close()
.addClass('fabric')
return part
}

To add the points, we’re using the `Point.flipX()`

and `Point.flipY()`

methods
here. There’s a few new Path methods too, like `close()`

and `addClass()`

.

Perhaps you can figure out what they do? If not, both the Point documentation and the Path documentation have detailed info on all the methods available, including these.