Why would this be making so much lag while the vector3 is being done?
Is the lag problem due to the vector'ing?
All the parts (15 parts) should line up together. Why wont they?
local Ts = TrailParts
local Mag = ((Ts[i+1].Position-Ts[i].Position).magnitude) -- Error here.
print(Mag) -- >> 0,0,0,0,0,0,0,0,INF,0,0,0,0,0 (Output)
--Ts[i].Size = Vector3.new(1,Mag,1)
Ts[i].CFrame = CFrame.new(Ts[i+1].Position,Ts[i].Position)
*CFrame.new(0,0,-Mag/2)
*CFrame.Angles(math.pi/2,0,0)

1 comment
My guess is that the problem is you're getting the magnitude of a point, giving a magnitude of zero or infinity. Based on what you put, I think you're trying to make the size of the part (Ts[i]) based on two corners given by Ts[i+1].Position and Ts[i].Position, so you might have to do that by calculating each vector component (x, y, and z).