The rotated rectangle tool is a special mode for easily drawing rotated rectangles by manually digitizing 3 corners, and conforming to 90 degree square corners. This mode will create a rectangle feature with 90 degree angles by defining three of the corners. This is especially useful for digitizing buildings and other rectangular area features off of imagery or other reference data.
Select Create Rotated Rectangle (3 Point Draw) from the Digitizer menu or right-click context menu under Create Area/ Polygon Features to create an area feature, or under Create Line Features for a line.
Once selected, the cursor will indicate which type of feature will be created, showing either 
Line or 
Area icon. Left-click to start the rectangle,
then left-click again at the end of the first side, then left click again
when the rectangle shape is completed to create it.
Once the shape is finished, release the left mouse button and the Modify Feature Info dialog will appear allowing you to setup the label, classification, drawing style, and attribution for the new feature. See Editing Feature Attributes and Drawing Styles for more details.
Once the shape is completed, the Digitizer Tool will remain in the selected shape creation mode. Left-click to start drawing a new 3 point rectangle, or right-click to choose a different mode.
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