The problem is sometimes solidworks let me do so and sometimes it won't. Usually I just move the mouse pointer close to the edge but that works like 50% of the time I guess.
You can use edge and other filter in sketch mode.
I tried that but it won't let me select the edge this time. I was able to do so a moment ago though. Like I said, sometimes it works and sometimes it doesn't. This is the issue. I want to be able to select the edge on demand.
Unfortunately, this is not an ordinary edge, it is the edge of the silhouette that is variable in the 3D window and hence these problems. The only solution is ... precision?
Convert Entity or Intersection...
In first way is necessary select this edge too for convert
Second is OK but only if this edge is on sketch plane - It's not always like that. Look allow.
Retrieving data ...