contours disappear in flat areas when contour interval is changed

[apascavage]

To all:

I am recreating and checking a detention pond  that is surrounded by an earthen berm that is flat on the top.  The surface I recreated was generated from 3D Faces as I only had triangles and a boundary to use to regenerate the surface.

When I change the surface style so that I see 0.1 minor contours and 0.5 major contours, I lose the contour at the top of the pond which is at 616.5 all the way around.  When I switch the contour interval to 0.5 (minor) and 1.0 (major), the 616.5 contour magically appears!  Note that the base elevation is set to 0.00.

If I add a grade break line at elevation 616.55 in the middle of the top of the berm, the 616.5 contour appears with the 0.1/0.5 contour interval.  But I am not at liberty to add any grade break lines as I am only checking the work.  Besides, I can get the contour to show at a different interval, but it is not at the desired interval.

Any help is most appreciated.

AL P.

[C3D_User]

I know exactly what you mean, as I have ran into the same situation.  You nailed it by saying adding a breakline/grade break line at 616.55; intead of that do one at 616.51.  Your not changing the surface that dramatically.    

[nbrimer]

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@apascavage wrote:

When I change the surface style so that I see 0.1 minor contours and 0.5 major contours, I lose the contour at the top of the pond which is at 616.5 all the way around.  When I switch the contour interval to 0.5 (minor) and 1.0 (major), the 616.5 contour magically appears!  Note that the base elevation is set to 0.00.

If I add a grade break line at elevation 616.55 in the middle of the top of the berm, the 616.5 contour appears with the 0.1/0.5 contour interval.  But I am not at liberty to add any grade break lines as I am only checking the work.  Besides, I can get the contour to show at a different interval, but it is not at the desired interval.

Any help is most appreciated.

AL P.

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The reason that it doesn't show at the interval without that brake line is because your setting the interval at a whole numbers 1 & 5. Also if you want to show the top of the berm elevation without a contour showing it you could also use the point spot lable at a few places around the pond so you can truly say you did not change anything