The AngularVelocity property is a DataType/Vector3 which determines the goal angular velocity a BodyAngularVelocity should maintain through the exertion of torque. For this property, the direction of the vector is the axis of rotation. The magnitude is the angular velocity in radians per second. By default, this property is (0, 2, 0).

Tip: You can multiply a DataType/Vector3 by math.rad(360), or 2π, in order to convert angular frequency (rotations per second) into the desired angular velocity (radians per second). For example: Setting BodyAngularVelocity/AngularVelocity|AngularVelocity to Vector3.new(0, 1, 0) * math.rad(360) ≈ Vector3.new(0, 6.283, 0) will cause a part to spin around the Y axis once per second.

To better understand how the axis of rotation is determined from this property, imagine that there is an axle running between the part’s position and the part’s position plus this property as a global offset. This axle determines in what orientation the object will spin. The length of the axle determines the angular speed in radians per second. In the animation below, the Part contains a BodyAngularVelocity and is floating in the air (using a BodyPosition). The BodyAngularVelocity has the default AngularVelocity of (0, 2, 0), and this vector is visualized with a superimposed green line. It represents the axis of rotation. If we were to make the axle longer, like (0, 4, 0), the part would spin faster.

As for the direction of rotation (counterclockwise or clockwise), use a right-hand rule: make a thumbs up with your right hand, and point your thumb it in the direction of the vector. The direction in which your fingers curl is the direction of the goal angular velocity.