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 comment:

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


Related Posts Plugin for WordPress, Blogger...