When you are at the point of selecting a location during a drawing command (and you wish to use Inference), hold [Shift] and move the cursor over an object in the drawing. As the object falls within the outer entity trap (the outer box displayed around the cursor cross-hairs), the object’s nearest attachment location will be displayed as a pop-up message on the cursor. As you move the entity trap along the selected object (keep holding [Shift]), watch the message: it will change to correspond to the various features of the object. When you find the attachment location that you want to use, left-click and the entity will snap to the selected location. Release [Shift].
Important:
Inference also enhances speed and precision during joining, moving, rotating, stretching, or copying procedures. Almost all drafting or editing functions can be accomplished with greater accuracy by using the Inference Engine.