To Create an Offset from Two Elements

With a tool active, use AccuSnap to display a tentative point at the keypoint of the first element (or place it manually).
Press the <O> shortcut key.
The compass moves to the tentative point location.
On the keypoint of the second element, use AccuSnap to display a tentative point (or place it manually).
Press the <X> or <Y> key.
AccuDraw responds by locking the dynamic line to the appropriate X or Y axis, but at the offset from the first tentative point to the second one.
Do one of the following:

Use another tentative point to lock the remaining axis of the tentative compass location.

or
Enter a data point to set the second axis value.

AccuDraw relocates the initial compass to the new indirectly derived location. From here you can continue the use of the current drawing tool.

Creating an Offset from Two Elements