Things You'll Need
Instructions
Place an object in the terrain.
Press "Spacebar" or "Esc" to enter select mode.
Select the object. Use your mouse pointer to click on the object you wish to rotate.
Hold down the "Ctrl" key.
Click and hold the left mouse button on the ground outside of your object. Clicking closer to the object allows you to rotate more quickly, while clicking farther away gives you more control.
Draw a circle around the object with your mouse pointer. The object will rotate according to the movement of your mouse. Continue until the object has reached the desired rotation
Release "Ctrl" and click elsewhere to deselect the object and continue building your map.