Select the object in Build/Buy mode
Press and hold the right mouse button while dragging to rotate on PC
Use the comma and period keys to rotate on PC
Press the left and right bracket keys to rotate on PC
Hold Alt while placing to freely rotate on PC
Use the bumpers/triggers on console to rotate objects
Use the rotate controls shown on screen for console
Press R to rotate on Mac
Use the same rotate keys or controls while the object is selected
Hold Shift while rotating for finer placement on some setups