How do I draw a right triangle when I only have the hypotenuse?
First off, I'm doing this on roblox, so remember that I'm dealing with three axes. But it is a triangle, not a pyramid. I'm using raycasting.
I have the hypotenuse (AB) already drawn, so I know how long it is and everything. I also have the position at the start and the end of this hypotenuse (in 3D roblox space). I have the direction that AC needs to travel. I just don't have the length of it.
That's what I'm trying to find. There's not really any code to show, because it's all correct. My methods are just wrong, and I can't figure it out. Hopefully this is possible. Explain it in layman's terms, please.
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If I understand your question correctly, what you're asking for is called vector projection.
Given a vector v and a direction d, find the vector y that points in the direction d but is the "same amount in that direction as v"
Formally, y = x * d + p where x is a real (the distance AC), and p(C-->B) is perpendicular to d (A-->C)
You can take the dot product with respect to the unit vector d to yield the equatoin
y . d = x * d.d + p.d. Since d is unit and d is perpendicular to p, this simplifies to x = y . d.
Thus the distance is given by, in Lua,
local distanceInDirection = vector:Dot(direction) -- e.g., local A = Vector3.new(10, 50, 30) local B = Vector3.new(18, 36, 7) local direction = Vector3.new(-1, -1, 0).unit local vector = B - A local x = vector:Dot(direction) local C = A + x * direction
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