Curve calculation

[TruyalYT]

Here’s what I mean:

Behind the ControlPart = Rotates strangely

[TruyalYT]

I mean StartPart not ControlPart sry*

[DataSigh]

I think it might just be a math problem. I’m testing it out in my studio and if all three parts (start, end, control) are lined up on any axis, when it turns the rotation on the control is too steep for it to look natural. If you move the control to the side it will look better.

red is end
green is start
blue is control

on here, all three parts are lined up and the turn is really steep

But if you move the blue off the alignment to the side, the rotation is smoother

[TruyalYT]

Yes… is there any way to fix this?

[DataSigh]

try this: (just copy paste it into the studio command bar)

local StartPart = workspace.StartPart
local ControlPart = workspace.ControlPart
local EndPart = workspace.EndPart
local numPoints = 10

local tempFo = Instance.new("Folder")
tempFo.Parent = workspace
tempFo.Name = "THIS IS THE CURVE FOLDER"

--starting up direction
local up = Vector3.new(0, 1, 0)

for i = 1, numPoints do
    local t = i / numPoints
    local slerpPosition = StartPart.Position:Lerp(ControlPart.Position, t):Lerp(ControlPart.Position:Lerp(EndPart.Position, t), t)

    local nextT = (i + 1) / numPoints
    local nextPosition = StartPart.Position:Lerp(ControlPart.Position, nextT):Lerp(ControlPart.Position:Lerp(EndPart.Position, nextT), nextT)
    
    local direction = (nextPosition - slerpPosition).Unit

    --compute the new up direction
    local right = up:Cross(direction).Unit
    up = direction:Cross(right).Unit

    local newPart = Instance.new("Part")
    newPart.Size = Vector3.new(1, 1, 1)
    newPart.Anchored = true
    newPart.Position = slerpPosition
    newPart.CFrame = CFrame.fromMatrix(slerpPosition, direction, up)
    newPart.Parent = tempFo

    ---orientation marker
    local marker = newPart:Clone()
    marker.Size = Vector3.new(0.2, 1, 0.2)
    marker.CFrame = newPart.CFrame * CFrame.new(0, 1, 0)
    marker.Color = Color3.new(0, 1, 0)
    marker.Material = Enum.Material.Neon
    marker.Parent = newPart
end

[TruyalYT]

Ok, yes, that generally works, but when I move the curve it gets weird

[DataSigh]

Can you send the code you’re using to move it? I’m not running into that issue

[TruyalYT]

local StartPart = workspace.StartPart
local ControlPart = workspace.ControlPart
local EndPart = workspace.EndPart
local numPoints = 10

local tempFo = Instance.new("Folder")
tempFo.Parent = workspace
tempFo.Name = "THIS IS THE CURVE FOLDER"

local up = Vector3.new(0, 1, 0)
local function Update()
	for i, Part in pairs(tempFo:GetChildren()) do
		if Part.Name == "Part" then
			Part:Destroy()
		end
	end

	
	for i = 1, numPoints do
		local t = i / numPoints
		local slerpPosition = StartPart.Position:Lerp(ControlPart.Position, t):Lerp(ControlPart.Position:Lerp(EndPart.Position, t), t)

		local nextT = (i + 1) / numPoints
		local nextPosition = StartPart.Position:Lerp(ControlPart.Position, nextT):Lerp(ControlPart.Position:Lerp(EndPart.Position, nextT), nextT)

		local direction = (nextPosition - slerpPosition).Unit

		--compute the new up direction
		local right = up:Cross(direction).Unit
		up = direction:Cross(right).Unit

		local newPart = Instance.new("Part")
		newPart.Size = Vector3.new(1, 1, 1)
		newPart.Anchored = true
		newPart.Position = slerpPosition
		newPart.CFrame = CFrame.fromMatrix(slerpPosition, direction, up)
		newPart.Parent = tempFo

		---orientation marker
		local marker = newPart:Clone()
		marker.Size = Vector3.new(0.2, 1, 0.2)
		marker.CFrame = newPart.CFrame * CFrame.new(0, 1, 0)
		marker.Color = Color3.new(0, 1, 0)
		marker.Material = Enum.Material.Neon
		marker.Parent = newPart
	end
end

EndPart:GetPropertyChangedSignal("Position"):Connect(function()
	Update()
end)

Update()

[DataSigh]

Welp, that was a fun way to spend my day. Attached the game file below

bezierStuff.rbxl (52.7 KB)

[TruyalYT]

OMG you are the nicest person I know here, the fact that you sat down and tried to help me for free is really not a given. THANK YOU SO MUCH really!

[DataSigh]

There’s also a cubic bezier curve right beside the main blocks where you can move both parts to make a cooler curve

[TruyalYT]

I could really use your help more often if I come across problems like this again. I don’t know anyone else who knows this area as well as you