Here is a hack for adding a center line to a detail view. Before we get going if Fusion 360 had a "Break View" (Create a foreshortened view with a section of the part removed) command I would have used that instead. But, here we are.
When you have a design that is long, sometimes showing its entirety in a drawing view leads to dimensions going to features that are hard to make out when printed.
This is exactly what I ran into. I wanted to have the middle of my design "blown up" on the drawing so the end user could tell exactly what edges the dimensions are going to. In my case, I wanted to identify and dimension off the center of the part. Since, there is no "Break View" command the only thing I could do was to use the "Detail View" command and show the middle of the design. Here lies the problem. The "Center Line" command requires picking two edges to identify where the center line is placed. The newly created "Detail View" isn't showing the two ends to create a center line.
Fusion offers the ability to sketch on top of the view but, it is very limiting and there is no good way of locating the "center line" accurately. Even if you could locate the line it can produce incorrect dimensions depending how the are placed. If you click on the sketch geometry first it pulls a dimension from the "Sheet" and likewise, if you click on the parts edge first it pulls a dimension referencing the model. Not to mention that the dimensions seem to always go in as "Disassociated Annotations" and you can never be re-associated.
The only viable solution for me was to create a sketch in the model and name it "Center Line" then turn on the visibility in the view. Note, the line cannot be a construction line because it will not show in the drawing view. The line must be a "normal" line. The added benefit here is the sketch and drawing dimensions are parametrically linked so when the design changes the drawing will update accordingly.
Autodesk is currently planning on a "Break View" command but, it appears to be something in the future. You can read it for yourself here.
Hope this finds you well and helps out in some way! Time to go sweep!