Problem with Bezier curves *control* point

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#1

Hello everyone,

I’m making a car system in my game, where npc cars will be animated, driving around my city.
I have multiple points which I tween the cars between.
I haven’t run into any problems until I approach turning around corners realistically.

I read this post prompting the idea of using bezier curves, however I’m struggling on finding the midpoint of the curve.

I managed to calculate it using this:

local midPoint = Vector3.new(carPos.X,carHeight,turnToPos.Z)

image

But this only works at certain rotations:

image

I’ve also tried using CFrame:ToObjectSpace, but this didn’t make any difference.

Is there any way to do this?

#2

That isn’t the midpoint, that’s the second (out of four) control point. The midpoint if obtained by taking the curve position when t = 0.5. Keep in mind that this is not the midpoint in terms or arc length, the the midpoint in terms of time.

#3

Sorry, that’s what I meant. Is there a way to find the control point?

#4

There’s no finding it, you provide it when you create the curve…? Do you mean find what the control point should be for a specific turn?

#5

I thought there would be a way to generate one since all curves are at 90 degrees. It would’ve been nice to not have to specify for every single corner in the city

#6

You can generate the control points however you want but it kinda sounds like you want a Hermite spline instead, which lets you specify two endpoints and two velocities. The Continuity of Splines - YouTube

#7

Thanks, I’ll give this a try! character limit

#8

Thank you in advance.

I have solved my own problem, through use of the following code:
local function calculateBezierCurvePoint(carPos,carHeight,turnToPos,dist)
local midPoint = Vector3.new(carPos.X,carHeight,turnToPos.Z)
local bezierVector = midPoint - turnToPos
local bezierCurvePoint = turnToPos + (bezierVector.Unit*dist)

return bezierCurvePoint

end

local function calculateBezierCurve(carPos,carHeight,turnToPos,dist)
local bezierCurvePoint = calculateBezierCurvePoint(carPos,carHeight,turnToPos,dist)

local bezierCurve = TweenService:GetBezierWaypoints(carPos,bezierCurvePoint,turnToPos)

return bezierCurve

end