How to correctly limit BodyGyro from rotating X and Y axes

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#1

I’m having a problem with limiting a BodyGyro from rotating the X and Y axes of a part. I want the part to be able to rotate on the Z axis so that when a player steps on the part, the part will only rotate on the Z axis but not on any other axis. This will be done using a BodyPosition and a BodyGyro, but it seems to not be working.

This is what the function for creating the BodyMovers for the Part looks like:

local function PhysicsAnchoredPart(Part)
	local Position = Instance.new("BodyPosition", Part);
	Position.MaxForce = Vector3.new(1, 1, 1) * math.huge;
	Position.Position = Part.Position;
	local BodyGyro = Instance.new("BodyGyro", Part);
	BodyGyro.MaxTorque = Vector3.new(
		Part:FindFirstChild("LockY") and math.huge or 0, 
		Part:FindFirstChild("LockX") and math.huge or 0, 
		Part:FindFirstChild("LockZ") and math.huge or 0
	);
	BodyGyro.CFrame = CFrame.new(Part.Position, Part.Position + Part.CFrame.LookVector);
	Part.Anchored = false;
end

This is what the part looks like in game:

There is another method of doing this using a hinge, but I’m not sure why this method doesn’t work? The part has IntValues named “LockY” and “LockX”, and the part also is oriented in a way where rotation in the Z axis should not change its LookVector. Why does it start moving frantically like that when there is a force applied to it by a character?

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#2

I suggest looking at AlignOrientation instead because you can make it rigid using AlignOrientation | Roblox Creator Documentation to prevent XY axis movement and you can control which axis it rotates in using AlignOrientation | Roblox Creator Documentation.

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#3

Thanks for the reply, this definitely solves my problem but I’m still looking for an explanation as to why this method wouldn’t work.

#4

Hmm, shouldn’t it be LockY and LockZ instead of LockX based on how you input them into max torque?

Y axis rotation should be zero. X rotation and Z rotation should be the one with math.huge applied onto them.

#5

That’s what I was thinking and I tried changing it, but the Part is oriented with the front of the part facing the next platform, so theoretically it should still work either way.
I tried changing the part’s mass to 0 thinking that it was the rotational inertia from the force of the character standing on the platform, and this is what happened:

https://gyazo.com/86c1df5bd0b69795bd41131d457b75c1

It acts more like how I want it to but it sometimes completely rotates 180 degrees in the X axis because of gimbal lock. So I’m pretty sure the issue was because of both rotational intertia and gimbal lock.