Snapping or aligning to a sloped surface in section

[chughes]

Is it possible to align or snap to a sloped surface that has been cut by a section plane?  IE, I have a section through a roof slope and would like to add 2D detail elements to the section cut.  However, I cannot align my 2D element to the cut through the sloped portion.  Please see below for reference.

Thanks.

[chughes]

Apologies if the question was unclear.  I was in the middle of working on a project and cluttered the question with project context.  To clarify, I started a new project with only the elements I am asking about.

New project.  Drew a simple hip roof with 2 assembly layers, the core and a substrate.  Cut a section down slope through the roof.  Go to the section view.  I labeled the section for clarity.  See the the images and video for additional clarity.

Videos

https://streamable.com/a7fnu

https://streamable.com/3abgc

Not trying to beat a dead horse with a cast iron pan, I just want to make sure of the correct answer.

Thanks for your help.

[cbcarch]

Try placing a Reference Plane BEFORE cutting the section. Then place the section along the ref. plane.

Make the ref. plane active/current.

Go to section and you should be able to place elements on the workplane set to your ref. plane.

(I have not tested this on your example, but see if this method works.)

[barthbradley · Accepted solution]

@chughes: I think we got. That's the way it is. So, the question is: how to align?

Personally I favor nudge approach, especially when dimensions aren't going to be pulled from the element. Also, as soon as you turn off Thin Lines, how much inexactness are you actually going to be able to detect in the view.  

That's my suggestion. But, if you need it dead  on accurate: go with @ToanDN approach.  

[barthbradley]

Dead on Accurate. It's an industry term. 

[ToanDN]

It proved if I sell my house only my agent is making money.