I agree that the contours for the most part should be perty, but I don't think as an industry we should be spending the amount of time and energy on smoothing contours as we do.
From an economic standpoint it saves money and makes a firm more profitable. For instance I was working on a project that transitioned from the top of a designed slope to existing ground a non uniform distance from the wall. With each design iteration we did the other engineer wanted the contours to be smooth. I spent 2 to 3 hours for each iteration to smooth contours and we did 4 to 5 iterations for one submittal. So that's about 15 hours of work wasted on making the contours perty for just one submittal. Did it make the design better? Did it make the project easier to build? Both answers would have to be no. I think the better answer would be to educate others that the smooth contours won't make the design better. The contractor is in reality going to build the squiggly contours. The surveyor is going to stake out the project from a line and then the grade checker is going to set temporary stakes perpendicular to the line down the slope to the top of the wall. If we connect those points after the project is built we should get the some squiggly contours, they will not be smooth like the plan shows. Essentially I was taking how the project was going to be constructed and then making up lies to get the contours to be smooth. Actually for the smoothing I was doing I'd feel sorry for the surveyor and grade checker if they actually had to build to the contours. They'd probably need a ten foot stake to fit all of the slope change information in some spots on the slope.
Since being green is fashionable today, there's the energy expended on making the changes. I could have reduced the carbon footprint of the project by not doing the contour smoothing. Think of the tons and tons of carbon we collectively could reduce if we didn't spend needless time smoothing contours.
Then there's also the technological advancements since the idea of using contours to show the design intent. If we want accuracy we need to provide the contractor with a digital model for use in a GPS system to grade the site. That way the blade of the dozer or grader knows exactly where it should be as it traverses the site. The technology is there it's just the adoption which is lagging.
Mathmatically and engineering wise the squiggly contours are correct. They follow the rules of TIN creation and what information the designer has provided, therefore it represents the design intent. Once the contours are smoothed we start creating the lies the original poster indicated he doesn't want.
There are ways to reduce the squiggly contours:
- Using supplementing factors that are smaller than 100 and 1 when adding breaklines.
- Extracting a surface from gradings and then pasting them into the design surface, instead of exploding grading objects to get breaklines to add to the surface.
- Sequestering curves in parking lots with tangent lines of the curves. The tangent lines would reflect the slopes of the pavement in front of the curves.
- Avoiding the use of varies slopes and go with uniform slopes.
