Smoothing Surface - strange result

[Fuscha]

I'm planning a querry with lots of floors. For every floor I make a single surface which is made out of 3 lines. I want to smooth every single floor-surface that I make, to get beautiful contours for my final plan. Now I tried the standard grid based smoothing with a 1x1x1m grid. The problem is, the steep part of the floor turns out nicely, but the flat part which should have the same hight over the whole are gets lots of strange contours...someone knows why it is like that or maybe if another smoothing method would give me a better result?

Thanks, Tom

[tcorey]

Smooth the contours, not the surface.  See the Contours tab of Surface Style Editor.

[Fuscha]

Thanks for the fast answer!

Hmm but the contour smoothing is just a basic setting in the surface settings right? I can't do it after i created the surface it just adds date when i create the surface right?

I wanted to smooth because of another reason than the looks in the first place, because whenever I add my floor-surface to my main surface I get some contours in the flat area (see below, in that case it's just 1 line that got added, but sometimes it's way more) and I thought that smoothing will help but it got even worse 🙂

[jroot]

Hard to tell when it's zoomed out to see the big picture but the contours look pretty good before the smoothing.

It's been a while since I've done the smoothing but you can window an area to smooth, right?  Can you just not window the flat area?

Another thing to try would be to throw more breaklines in the middle of the flat area, maybe the smoothing would work out better with more info.

[Fuscha]

Yes you are right, I guess I'll keep the contours without smoothing they look ok, but which I still couldn't figure out is why I always get some contours added to the flat area when I add my floors to the main area, look at this:

[_Hathaway]

What is the origin of your data?  You can cleanly see the triangulation lines in your contours.  It looks like a very steep hillside which i assume? has a lot of trees???  You cannot make good data out of bad or lacking data. You'll need more data or a trip to the field to verify what you're seeing in your contours is correct (always a good idea to do this but not always practical).  We never smooth contours, ever.

[Fuscha]

My origin data are just 1m-contours that are made out of  a laserscan, the data is not bad or lacking. I just want to know why there are contours added in the flat area if i paste my floor-surfaces to my main surface althought the original floor-surfaces are 100% flat. When I look closely to my end surface it's not completely flat and that bothers me.

[MauCabrera789]

Earlier today I encountered the exact same issue in one of my surfaces. I did end up finding a work-around, so I wanted to post it here just in case somebody comes across it in the future!

After playing around a little with the surface, found out C3D sometimes bugs out like that when using nearest neighbor surface smoothing on sections of the surface that are completely flat and somewhat enclosed (i.e. imagine a circular feature line consisting of several vertices at the same elevation, with no further elevation data within). As you said, this problem happens in the flat areas of your surface and not in the steep areas.

The work-around is to vary the elevation of the points at the perimeter of this flat area by just a little bit (+/- 0.01 ft) so that C3D does not consider the region completely flat. If you're working with a very large data set, this might not be a feasible solution for you, but if you're working with a localized grading plan with smaller data sets, this might be a feasible work-around involving small amounts of manual work.