Monday, 30 April 2012

Civil3d Sections Composite Surface Slope Labels

If you are like me and do a lot of site earthworks you work with corridors, parts of corridors, gradings and breaklines to built up a finished composite surface. This is fine until you cut some section down one of your corridors and then want to label the slopes of your composite finished surface. If you try and use a segment label to add the percentage grade the first thing you will notice is you get alot of labels most of which you want to delete and you can not reduce the number of labels with weeding as it is greyed out.


To get partly around this limitation in Civil3d i use a grade break label with a number of expressions to weed down the number of labels that appear on the section by weeding on the change in angle of the section of the finished surface. Lets face it we are only interested in having a Labels when there is a reasonable change in grade.


I have the following expressions setup under grade break labels.

Weed Angle is just a place holder for the grade you want to weed by in this case 3% so you do not have to go into the more complex expressions.

GradeChange is  Section Grade In – Section grade Out

Text Height Based on Weed Angle is main equation and the tricky way to hide the labels you do not want to see by reducing their height to some thing really small. First I check to see if the grade is near infinity with and if and if true make the label 0.01mm high the smallest value you are allowed. Next I check the Absolute value of the Grade change against the weed angle. If the change in angle is smaller than the weed angle I make the label really small (aka hidden) other wise I make it just the normal height.

GradeOutToDegrees is used to get the angle at which the label should be rotated to be parallel with the out going section segment of the surface.

Once all the expressions are complete it is just  a matter of referencing them in the label.

I suggest when you start with expressions you add them to a check label to see what answers you are being returned so you can see what way to head.

How this method is by no means perfect and sometimes labels are missed in key areas. No problem just click one label you can see to highlight the grips of all labels present in the drawing.

Now select the grip on the section line of the label you want to show and drag it a small amount to have the label appear. Now instead of deleting useless labels you are just showing the ones you want. HTH


  1. Nice post. Looks like a good solution. I will have to give that a try.

  2. Hi Justin

    Given that we use the information generated in civil 3d in other software such as surfer and hecras.......

    And given that the software has limited access to information.

    Is there a solution to reduce the number of consecutive vertexes by applying a gradient between them and deleting vertexes.

    Of course, I do not want to use a simple surface method , Because I do not want to reduce the precision of work to continue at civil 3d.

    Just in the report or draw section view.

    I will be very grateful for your advice.

    Reza Monemi

  3. Reza

    I am sorry apart from using the weeding factor and maybe now offset labels or code set labels on your corridor and the above method I do not know any other way to reduce the labeling of vertices.

    If you cut your sections along the corridor model I have seem that you can manual edit each section with a manual over ride to to this you ctrl + click thinks in the section view. Is very slow process to do and you can lose track of what areas you have manually adjusted.




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