I just received this from Support confirming as a known issue. Hopefully this will help others not waste their time on this like I did all of yesterday and the day before. Also I would have to advise you not to bid your projects thinking your team can use QTO.
Please put your pressure on the Civil 3D management team to fix this as soon as possible.
@fcernst wrote:
Sure. Here you go:
I just tested this in C3D 2016 and it's still broken. I also found that the area reported by a feature line is also just the top 2d area, not the real 3d area of the feature line. This is probably related since corridors use feature lines as well.
Here's a screencast showing the feature line reporting an incorrect area.
I just tested this in C3D 2016 and it's still broken. I also found that the area reported by a feature line is also just the top 2d area, not the real 3d area of the feature line. This is probably related since corridors use feature lines as well.
Here's a screencast showing the feature line reporting an incorrect area.
To be fair, what you have is the second simplest case, with the first being all points at the same elevation. If you have more than 3 vertices and varying elevations on the vertices, then chances are the shape is not planar and in that case you do not have an area that can be calculated directly from the vertices. See Area of the minimal surface of a non-planar quadrilateral in 3D
So what is Autodesk reasonably expected to do in this case? My answer would be they should just label the area as "2D Area" and be done with it.
The next level of complexity would be for Civil 3D to check if the feature line vertices are all planar and calculate the 3D Area. Since the real life occurence of all points being planar is probably small then I would say there is no point to this. Another option is to triangulate a surface inside the area and list an "Approximate 3D Area".
Neither of those are reasonable solutions for a value in the properties palette so again, I say just list it as 2D Area in the properties palette and be done.
I just did a quick corridor test and the QTO 3D calc seems to work in 2016.