Creating a body between two lines (not surfaces!) on curved surfaces?

[Anonymous]

First, I'm pretty new to Fusion 360 in general so this question might be really poorly worded or otherwise just a really simple thing, sorry and thank you in advance! Second, I'm ATTEMPTING to generally follow "best practices" by making sure things are fully constrained, etc, but likely I'm doing a lot wrong - overall I'm OK with not being perfect as I'm pretty close to "done" with the design I am building and so far so good, other than this one issue!

Now, the basic question is this: I have a curved "face" of a box I'm building, and I have 12 holes through the face of this box. What I want to do is at the front of each hole, model a little "cap" that fits flush into each hole. 

If you look in the screenshot below, there are two "circles" highlighted - I basically want to make the space between these two circles a new body. The problem is that these are not actual parts of a sketch, they are just lines where a `loft` "cut" the surface (sorry, I feel like this is really difficult to explain clearly, hopefully it makes sense to somebody :)). 

So I can't loft between these two lines to make a body, and I can't project a line to make a new surface to loft from because the surface is curved.

I feel like there is probably a very simple way to do this, or perhaps the way that I originally created the "hole" in the body (with the "cut" between two circles which you can sort of imagine from the second screenshot) made this an impossible or difficult thing to do?

Thanks for your help!

[jeff_strater]

The problem is that those circles are not profiles or sketch entities, so the cannot be selected for a solid loft today.  You can make a surface loft from those edges, which can be a step in the process of getting a solid body.

two approaches offhand.  If one face is planar, you can sketch on that face.  If not, you can use Include 3D Geometry to insert both edges as 3D geometry.  In my simple case below, the geometry is planar, so it's pretty easy.  The other way to do this is use Surface Offset to copy the side face of the hole, then use Patch to close the end faces.  Lots of options here, this just illustrates a couple.  If you share your design, get can get more direct help

[jeff_strater]

screencast did not post.  Try again.  In case it fails here it is:  https://knowledge.autodesk.com/community/screencast/e2fc88d6-fde4-4682-9214-c45dec470cc8

[etfrench]

Try an Extrude with a taper angle.  If this doesn't work for you, attach your file to the thread.

[Anonymous]

Thank you so much for taking the time here, this was really helpful. 

That said, in the end I ended up using the `Surface` -> `Patch` tool to create a surface from the lines, and then I was able to loft between the two surfaces. this seems to have worked pretty well, though I suspect I may have broken one or two "best practices" while doing this (not sure, just guessing!), mainly because there was what you might call a "process smell" - I had to patch every single one of the holes on both lines, so 24x patch... probably a better way to do this but the end result is what I was looking for!

Thanks again all for hte help / feedback!