hi I’m trying to do something like this.

the cyan line is the ray and I’m trying to get the position of the red dot without having to place a part on the y position and cast another ray to find out.

Anyone know how to do this?

hi I’m trying to do something like this.

the cyan line is the ray and I’m trying to get the position of the red dot without having to place a part on the y position and cast another ray to find out.

Anyone know how to do this?

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You can find it by rearrange the vector line equation

```
local rayOrigin
local rayDirection --Components of a ray
--Vector equation of a line, pointOnALine and positionAlongLine and DirectionOfTheLine are all Vector 3.
positionAlongLine = pointOnALine + DirectionOfTheLine * X -- X is a scalar parameter
--Solving for only the y component to find when Y = 2
y = rayOrigin.Y + rayDirection.Y* X -- y is a y position on the line, X is a scalar parameter
--To find when y = 2
2 - rayOrigin.Y = rayDirection.Y*X
--therefore
X = (2 - rayOrigin.Y ) / rayDirection.Y
--Once you found X you can find the end result position by subsituting the X scalar parameter into the vector line equation.
--Notice the equation fails if the ray direction Y is equal to zero
local redDotPosition = rayOrigin +rayDirection*X
--Or combining the equations
local redDotPosition = rayOrigin +rayDirection*(2 - rayOrigin.Y ) / rayDirection.Y
```

Also keep in mind this equation is a line going both directoins and not a ray in one direction, For a ray the X scalar parameter is limited to X>0 meaning it c an only go along the rayDirection.

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