How do I make a part grow?

So, I have a part. It gets rotated and positioned according to the players torso's position and mouse.Hit.p

laser.CFrame = CFrame.new((start+pos)/2,start) -- start is player.Character.Torso.Position
laser.CFrame = CFrame.new(laser.Position,pos)*CFrame.Angles(0,math.rad(90),0)--pos is mouse.Hit.p

That's what does all the part's CFrame. I was trying to get one end of it to stay on the player and the other end to grow.

function grow(part,dis,start)
	repeat wait(0)
		local pos = Vector3.new(part.Size.X*2,part.Size.Y,part.Size.Z*2)
		local center = (pos+start)/2
		part.CFrame = CFrame.new(Vector3.new(center.X-start.X,center.Y,center.Z-start.Z),start)
		part.CFrame = CFrame.new(part.Position,pos)*CFrame.Angles(0,math.rad(90),0)
		part.Size = part.Size +Vector3.new(1,0,0)
	until part.Size.X >= math.floor(dis)
end

I changed this function a lot. The above is the latest attempt, and it failed so hard.

If I use:

function grow(part,dis,start,pos)
	repeat wait(0)
		local center = (pos+start)/2
		part.CFrame = CFrame.new(center,start)
		part.CFrame = CFrame.new(part.Position,pos)*CFrame.Angles(0,math.rad(90),0)
		part.Size = part.Size +Vector3.new(1,0,0)
	until part.Size.X >= math.floor(dis)
end

It grows from the center, and that isn't good.

I tried this.

function grow(part,dis,start,pos)
	repeat wait(0)
		local center = (pos+start)/2
		part.CFrame = CFrame.new(center,start)
		part.CFrame = CFrame.new(part.Position,pos)*CFrame.Angles(0,math.rad(90),0)
		print(part:Resize(3,1))
	until part.Size.X >= math.floor(dis)
end

And it did the same thing!

#Any help is appreciated

As far as my knowledge goes you can't resize parts from one direction, but what I can suggest is that you resize the part and move them to one direction. I'm not good at CFrameing and part positioning, so I can't make a suitable example, this is only a theory that I think it would solve your problem.