What you are referring to is the infamous 2 projection
curve. Never use it.
Do this instead. Extrude a surface from a plane as you normally.
Then Extrude another surface from an adjacent plane. Where they
meet creates an intersection. This is much easier to visualize and allows
a trail for others to follow.
I agree with Design-Engine. It is much easier to identify the two created surfaces than it is to figure out the 2 sketches used to make the intersected datum curve. If you do not like the surfaces, put them on a layer and blank them. Either way gets you the same result. Using the surfaces, makes it easier for a future user to identify how the feature was created.
so is it better to create 2 intersecting surfaces then merge them and
use the merge edge as, say, a sweep trajectory, or is it better to
create the 2 surfaces then intersect them and use the resulting curve
feature as, say, a sweep trajectory?
The isdx and sketch do not intersect. I would imagine an extruded surface and an intersect at that point would work.
As far as my .02...I never extrude two surfaces to get an intersection, instead opting for the 2 curve approach. I can't stand trying to layer every little thing off...it's too time consuming and I can't think of that many unique layer names. Surfs that are close to one another or are very close in intent are way too hard to differentiate in my opinion. Dealing with all the extra unnecessary surfaces is a waste of time as well in a resolve situation. U..G..L..Y! Besides WF will automatically hide the sketches.My models are much less cluged by not having so many construction surfs.(sounds like the old days of Catia and UG).I add feature names where it makes sense to point subsequent moders in the right direction.
You will help the next person by keeping the model clean of extra crap more than having every step mapped out graphically IMHO.