Create panel > Helpers > Standard > Object Type rollout > Protractor
Tab panels > Helpers tab > Protractor Object
Protractor measures the angle between any two objects in your scene.
The names of the two objects appear above their respective buttons, and the angle formed at the protractor object between the pivot points of the two objects is displayed in the Angle field. Lines are drawn between the protractor and the two selected objects.
The line to the first selected object uses the Target Line color (set in Customize User Interface dialog> Colors panel > Gizmos group), and the line for the second selected object uses the color of the protractor. Set the protractor color by choosing Tape Object from the Objects group in the Colors panel. The same color is used for the Tape Object and the protractor.
You can reselect the protractor at any time, enter the Modify panel, and pick new objects to measure. You can move either of the two objects or the protractor itself to change the angle.
Note: If you need to watch the Angle readout while moving either of the objects, first select the protractor, then click the Pin Stack button. You can now select and move the other objects while the stack remains pinned to display the protractor angle.
Procedure
To use the protractor:
After selecting Protractor in the Create/Helper group, click in the viewport to place and create the protractor icon. You can also drag to move it before releasing the mouse button.
Click the Pick Object 1 button, and then select one of the objects in the scene.
The name of the selected object appears above the button.
Click Pick Object 2, and then select a second object in the scene.
Interface
Parameters rollout
Pick Object 1: Click this and select the first of the two objects whose angle you want to measure.
Pick Object 2: Click this and select the second of the two objects whose angle you want to measure.
Angle: Displays the angle between the two objects.