How do you model bezier curves with the beam curve property

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#1

How is the beam curve property calculated and how would you use it to model a quadratic bezier curve?

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#2

Roblox uses cubic bezier curves for beams
On the wiki page for beams it describes the curve sizes being calculated as:

P0 : The start of the beam, the position of Beam.Attachment0
P1 : Beam.CurveSize0 studs away from Beam.Attachment0 , in Beam.Attachment0 ’s positive X direction.
P2 : Beam.CurveSize1 studs away from Beam.Attachment1 , in Beam.Attachment1 ’s negative X direction.
P3 : The end of the beam, the position of Beam.Attachment1

Calculating these positions should be pretty self explanatory and would just involve multiplying the attachments CFrame by CFrame.new(curvesize0,0,0) or CFrame.new(-curvesize1,0,0)

You would then just use the bezier formula to complete the problem

function B(t,p0,p1,p2,p3)
	return (1 - t)^3*p0 + 3*(1 - t)^2*t*p1 + 3*(1 - t)*t^2*p2 + t^3*p3
end

beam.Parent.CFrame * B(t,attachment0.Position,(attachment0.CFrame*CFrame.new(curvesize0,0,0)).p,(attachment1.CFrame*CFrame.new(-curvesize1,0,0)).p,attachment1.Position)

Results in something like

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#3

Ah, i meant like how could you set the beam’s curve properties to a certain bezier curve not using it as a trajectory but using it as a projectile tracer.

#4

I got it to work by just doing the inverse of that. lol.

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#5

Hey would you mind explaining how you got it to work Mr. Ratius Rat? Thanks.

#6

Difficult to explain but essentially what you’re trying to do is changing the CFrame relative to the attatchment’s right vector and since it’s only quadratic i only edited the curvesize 1.

#7

Hm Do you have a video of how your tracers came out looking? (Visually) Thanks for responding.