Click the menu icon to enable this plugin.

After the plugin is enabled, select the required orthogonal projection view tab. Then click an hold on a control point of the surface to be rotated.

Drag the mouse to rotate the surface. Note that the surface rotates around the control point in the first row and first column of the control point grid. Note also that the angle of rotation changes as the mouse is dragged relative to the view origin. The angle is displayed in the mode text box above the 3D view.

Release the mouse to complete the rotation.

Click the menu item to disable the plugin mode.