- Tutorials
- Pattern design tutorial
- Part 2: Parametric design
- Drawing the bib outline
Drawing the bib outline
With our neck opening in place, let us draw the basic outline of our bib.
mjs
design/src/bib
function draftBib({
Path,
Point,
paths,
points,
measurements,
options,
part,
}
) {
// Construct the quarter neck opening
let tweak = 1
let target = (measurements.head * options.neckRatio) /4
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')
/*
* Drawing the bib outline
*/
const width = measurements.head * options.widthRatio
const length = measurements.head * options.lengthRatio
points.topLeft = new Point(
width / -2,
points.top.y - (width / 2 - points.right.x)
)
points.topRight = points.topLeft.shift(0, width)
points.bottomLeft = points.topLeft.shift(-90, length)
points.bottomRight = points.topRight.shift(-90, length)
paths.rect = new Path()
.move(points.topLeft)
.line(points.bottomLeft)
.line(points.bottomRight)
.line(points.topRight)
.line(points.topLeft)
.close()
.addClass('fabric')
return part
}
First thing we did was create the width
and length
variables to
save ourselves some typing:
Javascript
const width = measurements.head * options.widthRatio
const length = measurements.head * options.lengthRatio
Both the length and width of our bib are a factor of the head circumference. This way, our bib size will adapt to the size of the baby, and the user can tweak the length and width by playing with the options we added to the pattern.
Once we have our variables, we’re adding some new points, and a second path called rect
.
Javascript
points.topLeft = new Point(
width / -2,
points.top.y - (width / 2 - points.right.x)
)
points.topRight = points.topLeft.shift(0, width)
points.bottomLeft = points.topLeft.shift(-90, length)
points.bottomRight = points.topRight.shift(-90, length)
paths.rect = new Path()
.move(points.topLeft)
.line(points.bottomLeft)
.line(points.bottomRight)
.line(points.topRight)
.line(points.topLeft)
.close()
.addClass('fabric')
We’re calculating the topLeft
point so that the top edge of our bib
and the sides are equidistant from the neck opening.
We didn’t have to do that. But it looks nicely balanced this way.