When a command prompts you for a point, you can specify a precise location using coordinates, object snaps, and several other methods.
Your cursor locks onto the object snap location that you specified, and a marker and tooltip indicate the object snap location.
If more than one object snap is available, press Tab to cycle through the choices.
The cursor snaps to the specified geometric feature closest to where you selected the object.
Use object snap tracking to select a point along alignment paths that are based on object snap points. Alignment paths can be horizontal, vertical, parallel, or to a preset polar tracking angle.
Acquired points display a small plus sign (+).
Polar tracking guides the movement of your cursor to specified polar angles and angle increments.
The cursor snaps to the angles and increments defined in the polar tracking settings.
The grid is a rectangular pattern of lines or dots that covers the entire XY plane. Grid Snap restricts the movement of the crosshairs to intervals that you define. Grid and Snap are independent settings but are often turned on at the same time.
The cursor snaps to the closest grid point.
Relative coordinates are based on the last point specified. The last point specified can be from the same command or from a previous command.
For example, @2.5,1, specifies a point 2.5 units in the X direction and 1 unit in the Y direction from the previous point.
For example, @3<45, specifies a point 3 units at a 45-degree angle from the previous point.