How do I change the size of a part in just 1 direction?

I'm trying to make it so that, when you change the size of a part with code, the part will only scale in the direction I want it so. This is similar to how the scale tool will only increase the size of a part in the direction that you drag it.

So far, this is the only code I have

local part = workspace.part1

while true do
	part.Size = part.Size + Vector3.new(0,1,0)
end

There's a trick that you can do to mimic the effect of a part's size changing in one direction. You can do the inverse of what you're doing on the size of the part onto the position of the part and it'll look like the part is being re-sized in one direction.

For example: If you're adding 1 on the part's Y size, subtract 1 from the part's Y position to gain the effect.

Also, you must have a wait() in your loop, otherwise ROBLOX will crash because the loop is running too many times. A simple trick to do this is while wait() do.

Your code should look something like this:

local part = workspace.part1

while wait() do --Using wait() instead of true as you need a wait() in any loop, otherwise ROBLOX will crash.
	part.Size = part.Size + Vector3.new(0,1,0)
	part.Position = part.Position - Vector3.new(0,1,0)
end

I hope my answer helped you. If it did, be sure to accept it.

Haven't had much time to work on it, but this should work. Message me if you have any issues with this. I'm assuming the part is (1,1,1)

local part = workspace.part1

while wait() do
	part.Position = Vector3.new(0,0,0)
	part.Rotation = Vector3.new(0,0,0)
	local pos = part.CFrame
	part.Size = part.Size + Vector3.new(1,2,1)
	part.CFrame = pos*CFrame.new(0,0.5,0)
end