---
title: utils.curveIntersectsY()
---
The `utils.curveIntersectsY()` function finds the point(s) where a curve
intersects a given Y-value.
## Signature
```js
array | Point | false utils.curveIntersectsY(
Point start,
Point cp1,
Point cp2,
Point end,
float y)
```
This returns `false` if no intersections are found,
a [Point](/reference/api/point/) object if
a single intersection is found, and an array
of [Point](/reference/api/point/) objects if
multiple intersections are found.
## Example
<Example caption="A Utils.curveIntersectY() example">
```js
({ Point, points, Path, paths, Snippet, snippets, utils, part }) => {
points.start = new Point(10, 45)
points.cp1 = new Point(50, 10)
points.cp2 = new Point(0, 80)
points.end = new Point(110, 70)
paths.curve = new Path()
.move(points.start)
.curve(points.cp1, points.cp2, points.end)
for (let y of [40, 50]) {
points["from" + y] = new Point(10, y)
points["to" + y] = new Point(110, y)
paths["line" + y] = new Path()
.move(points["from" + y])
.line(points["to" + y])
.addClass("lining dashed")
}
snippets.i50 = new Snippet(
"notch",
utils.curveIntersectsY(points.start, points.cp1, points.cp2, points.end, 50)
)
for (let p of utils.curveIntersectsY(
points.start,
points.cp1,
points.cp2,
points.end,
40
))
snippets[p.x] = new Snippet("notch", p)
return part
}
```
</Example>
## Notes
This is a low-level (and faster) variant
of [`Path.intersectsY()`](/reference/api/path/intersectsy).
Instead of a path, you describe a single curve by passing the four
points that describes it.
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