I’m surprised that I don’t. At least until I see this thread on CADTutor. And it’s kind of relieved that many of the senior members don’t know it.
You can see how it works from nice animation from alanjt.
Still doesn’t work?
So how it works?
Activate parallel object snap
I thought we need to pick object/point after we activate the object snap. Just like when we’re working with other Osnaps. But no! You only need to hover above the line to make it as reference.
You should see the snap icon at your pointer.
Now move away your pointer until you see the rubber band line.
You can click a point to create the parallel line now.
I know it’s quite basic. But you might need it.