You can align the construction plane to any window by selecting a rotate handle and typing w for window. The plane then aligns parallel to the camera plane for the active window. You can use Snap mode to rotate the manipulator so the sphere' s axis points towards the snap point. To constrain a rotation, select a dotted arc to allow rotation about the axis perpendicular to the arc. This rotation axis is also highlighted.
Free rotation leaves a dotted line to show the starting position of the rotation.
You can undo this action at any time. In Snap mode, clicking on an arc selects the closest of the two spheres at its ends. In this mode, the plane passing through the rotate axis and the selected sphere rotates about the axis so that it passes through the snapped point. For more information on three-point planes, see How to Create a Three Point Plane, below. The scaling feature is turned OFF by default.