The program’s intelligent Collision Control feature prevents objects from being inserted where they do not fit. By default, Collision Control is on, but you can turn it off whenever you like using one of three methods.
To turn Collision Control on or off:
Press F9 on your keyboard, or
Click the COLLISION button on the Status bar, or
Select Settings > Program Settings, then on the Drawing Aids page, check or uncheck the Enable Collision Control (F9) check box
Note: Collision control affects building elements on the current building location only. It does not affect landscape elements.