Intersect two different Gradings

[owenmull]

Greetings,

I know I should know this, but can't seem to get it to work.

I have two ~parallel feature lines about 250' apart. I grade the Easterly Ft Line going west at a +1.5%, and I grade the Westerly Ft Line going east at a -2.00:1 slope.

I know C3D doesnt have a tool to intersect them, I must use the intermediate surface approach.

What I did was grade one, create 'Paste Surface 1' then grade the other, create 'Paste Surface 2' and then I created Surface 3 and pasted 'Paste Surface 1' and 'Paste Surface 2' into Surface 3. 

Throughout I used 'Grade to Distance'

Surface 3 doesnt come out correctly.

What am I missing? Could somebody more knowledgeable than I step me through how to accomplish this?

Thanks!

[peterfunkautodesk]

If the gradings are in the same site they will intersect. I just tried this with two lines and graded to a distance of 230 feet for each one and it worked fine.

The one thing i would make sure is if the parameters you set will intersect. FL 2 will need to be at least 3.75' above FL1.

Regards

Peter Funk

Autodesk, Inc.

[owenmull]

Thanks for the reply.

Yes, I was aware that the Feature Lines in the same Site will interact.

What I ended up doing was extending the first grading (horizontally) past the other feature line, creating a surface from that, and then Grading the other feature line to this surface.

From there I created a Paste Surface between the two, which created a seam between them.

[mathewkol]

Peter said that gradings in the same site intersect. You already know that feature lines interact but so do hgrading objects. Your workflow is a few steps too many. Gradings will just do it automatically.

[Neilw_05]

Per Peter's reply, the gradings will clean up where they intersect. (See attached).

[owenmull]

Matthewk:

Yes, I was aware of that. I havent had trouble with this in the past but these feature lines are not uniformly graded entities. i.e. Im not grading from elev. 1000' to elev. 900'. These feature lines more represented an EG profile, and varied in elev., making the intersecting grading seam a bit cumbersome.

[Neilw_05]

If you are trying to intersect 2 gradings that are targeting surfaces, then you may need to use intermediate surfaces.

This post has a similar scenario: http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Intersect-two-gradings/m-p/3385093#M173037

[owenmull]

Thanks, neil. I did know about that thread as I commented on it.

What I ended up doing was extending horizontally one grading past the other feature line, creating a surface out of that, and then (in another Site) grading the other to that Surface, and then when I created a Paste Surface, it merged the two like I wanted.

I knew what I wanted and where I wanted to end up, and knew I had to use the intermediate surface approach,m just took a little refreshing to get it done.

Thanks for the input guys!