I have a straight bit of duct and wish to use mate references to quickly attach a branch to it. As you can see from the image below the branches can face in two directions.
I can not figure out how to choose the direction with mate reference. When I click the lower end of the straight duct it attaches the branch facing up and when I click the top face of the straight duct is attached the branch facing down. How would I choose whether either of the branches are facing up or down. e.g. I would like the top branch to be facing up instead of the default down.