Surface Creation - By Points or Breaklines

[matttmiles]

I would like to get some opinions on which is a better method to creating a C3D surface. I want to get an accurate cut and fill for a proposed commercial lot which is mostly parking and 3 or 4 buildings. It seems to me that using a line command and adding two elevations on either side is the most accurate, but its so cumbersome and not very dynamic. Plus a curved island is modelled as a triangle. However, adding single points seems to create issues with interpolation.

Please let me know if you know any better methods, and thank you in advance

[tcorey · Accepted solution]

Consider using feature lines. This will allow the creation of 3d curves around your islands. When you add these feature lines as breaklines, pay attention to the mid-ordinate distance setting.

Feature lines around features, tops, toes, flowlines and points in open areas.

[ccoles · Accepted solution]

I also use feature lines. They provide a wealth of editing options including using the elevation editor and special editing tools, like relative elevations and pulling elevations from surfaces, and they allow for curves. And, added to the surface as breaklines, they are dynamic. So, changes update 'on the fly' as you make them, as long as the surface has automatic rebuild turned on.

[matttmiles]

Thank you both. I was just using a standard line and adding elevations on either end. I just found the convert polyline to feature line command thank to your suggestions.

[matttmiles]

How do you get the elevations to autofill between points? I've got a curb that has like sixteen points and I only have elevations for 4 points. The grades are different on eaither side of the elevation point but it seems like I can only do one grade in both directions in the elevation editor.

[johngordon6189]

You can add elevations from the feature line elevation editor. If you had an existing surface you could create the feature line and assign elevations from the surface, but that can generate some interesting results between known fixed points along the feature line. That's where the elevation editor shines.

[HorizontalCurveGuy]

Don't forget sites and infills