Add contour to surface

[Anonymous]

The brown line in the picture is the contour I wish to add to the surface. The yellow line is the contour of the surface after I added the contour. They do not match, especially in the acute angle of my contour. How to make them match? Thanks

[user181]

How did you add it to your surface? If you added it as a breakline you might want to add it as a contour instead.

[wfberry]

Did you add it as a break line?

Bill

[Anonymous]

no.

it is not a feature line. It is polyline. Should I convert it to feature line and then add as breakline? If this is the situation, why civil 3d has the function ADD Contour?

[wfberry]

You do not have to convert it to a feature line to add it to the surface as a breakline.

Bill

[user181]

Add as a contour (you can add a polyline as a contour to the surface)

[Anonymous]

Thank you.

That is what I did. My question is why the computer generated contour do not exactly match the polyline I added as contour?

[ArchD]

You may have to make some surface edits. Minimize flat areas works sometimes, other times you may have to swap edges.

[rkmcswain]

@Anonymous - mainly because contours are a representation of a known surface. They are not source data from which to build a surface.

The following explains it somewhat: https://knowledge.autodesk.com/support/autocad-civil-3d/learn-explore/caas/CloudHelp/cloudhelp/2016/...

Did you go through and understand all of the options when adding contour data?

https://knowledge.autodesk.com/support/autocad-civil-3d/learn-explore/caas/CloudHelp/cloudhelp/2016/...

[AllenJessup]

You need to review the "About Weeding and Supplementing Factors for Contours" section in the second link in the post by @rkmcswain. I believe that the Middle Ordinate will be the key factor but Weeding and Supplementing should be checked also.