I was recently teaching a custom Civil 3D class that involved some advanced grading and shared with the client some tips on use of Feature Lines and Grading Objects. I was able to show off the awesome powers of features and grading objects built in intelligence. That is how grading can interact with each-other.
If you still don’t know what I am talking about or have never seen it, what I am referring to is the ability that gradings created from separate feature lines in the same site and group, can clean up when they bump into each other.
Similar to the behavior of feature lines within the same site interacting with each other, grading objects in the same site will interact with each other too.
Then I took this idea and applied it to the more complex grading scenario presented by client, creating a pool. The given design parameters were 2 proposed feature lines, a known top of pond and know bottom of pond locations and elevations. From here, the need was to grade down from the top feature line and up from the bottom feature line and stop at the intersecting planes.
Initially the grading did not want to clean up and trim, but eventually they did interact. Not perfect results and quite a wild behavior.
Unsatisfied with what I was seeing, I created a case with Autodesk. It was recognized as an issue and sent up to the Development Team at Autodesk. The good news is that using other Civil 3D tools, we were able to work around this issue and create the necessary proposed design.