topic Re: Jagged contours from 1x1m .asc file in Civil 3D Forum

Jagged contours from 1x1m .asc file

Fuscha — Tue, 12 Jun 2018 13:35:14 GMT

I'm sry I recently posted a simliar topic but this time it's a bit different. I got an .asc file from a 3D-scan (see attachments) because I usually find that .asc make the cleanest surfaces (surface from DEM command) but when I make a surface out of the file it looks like the following images. I already googled for hours but smoothing the surface and all this commands don't help at all, so I guess it have to do with the .asc file? Maybe someone can help me.

Re: Jagged contours from 1x1m .asc file

rl_jackson — Tue, 12 Jun 2018 13:57:50 GMT

Your most likely going to need to reduce the amount of data in the surface. 1m x 1m is far to much information for a TIN surface so you'll most likely want to simplify surface wizard to reduce the overall amount of data. This will most likely have little if any effect on the overall surface.

I re-read you post if your using an ascii file to create the surface as a DEM, change it and dont use a DEM as that is a grid surface and you better served loading the ascii file as part of the surface definition as a point file. That should get elevate some of the issue, but you'll most likely still need to run the simplify surface wizard, for performance purposes if its a large area.

Re: Jagged contours from 1x1m .asc file

Fuscha — Tue, 12 Jun 2018 14:43:16 GMT

Thanks for the answer!

I don't think the problem is because of the amount of data, in the same project I'm using a 0,5m x 0,5m xyz-file with about 14million points which doesn't cause any troubles at all (sry I somehow can't attach the file, maybe because of the size)...it seems like Civil somehow have troubles connecting the single points from the point file.

I tried the following things like you said:

- Convert the .asc file to .xyz file with Global Mapper

- Created a surface with definition -> point file -> .xyz file

- used the simplify surface command

The .xyz point file instead of the .asc and DEM command didn't really change anything and the simplify surface command made it even worse 😛 although I don't really know how to use this commandafter simplify commandbefore simplify command

Re: Jagged contours from 1x1m .asc file

rl_jackson — Tue, 12 Jun 2018 15:06:38 GMT

You could try change the smoothing value of the surface properties, but once you do that, I think your going to see a noticeable change in file size.

The simplify surface wizard allow you to reduce the amount of data being used based on a percentage, so if you have 14milliion points and you simplify by 50% if will reduce the points being used by 50% or 7 million.

I think in your case you may be better suited in going to the Planning and Analysis Workspace (Map3d), importing the data into a Point Cloud and creating a surface from that.

Re: Jagged contours from 1x1m .asc file

codee — Tue, 12 Jun 2018 15:37:18 GMT

Here is what I got from the ASC file you shared.

I could not see the contours for some reason until I exploded the surface. After that I could see what was going on as shown below.

The reason for jaggedness I believe is just due to how the data exists. It is a raster data and it is triangulating to triangles that are about 1 foot.

The reason it is so jagged is because there is that much detail in the data.

Re: Jagged contours from 1x1m .asc file

rl_jackson — Tue, 12 Jun 2018 16:02:37 GMT

Also the data is on a GRID not a TIN this also makes a difference.

Re: Jagged contours from 1x1m .asc file

rl_jackson — Tue, 12 Jun 2018 16:21:45 GMT

I did this in C3D16 using a Point Cloud with a 50 intensity and then a further reduction of the data in the surface using a simply to remove 70%. But it gets a little better.

Re: Jagged contours from 1x1m .asc file

rl_jackson — Tue, 12 Jun 2018 18:28:24 GMT

I also did some additionally playing around with this and when you increase the contour interval, from 1/5m to 5/25m there is a lot less jogging in the contour lines, which tells me that although the information is provided at a 1m interval its not intended for that sort of display resolution. Maybe check with the data source.

Re: Jagged contours from 1x1m .asc file

Fuscha — Wed, 13 Jun 2018 05:58:02 GMT

Thanks for the help guys, I guess it's like you say that the troubles occour because of how the data is built up (1x1m grid). I can't use all that smooth and simplify commands since it would falsify my surface way to much or at least it would be way to undetailed then.

I actually ordered the data as .asc file because I thought that I get the best detail with it. I could also order 1m-contours (basic polylines) but I don't like how you don't have any data between the contours then, which is bad for larger flat areas with less than 1m difference in height.

Could you recommend me any file format expect from 1m-polyline-contours which would give me the best result and will work in Civil3D?

Re: Jagged contours from 1x1m .asc file

rl_jackson — Wed, 13 Jun 2018 12:06:51 GMT

"I can't use all that smooth and simplify commands since it would falsify my surface way to much or at least it would be way to undetailed then."

It might be a good idea to hire a surveyor (or by a drone), if you need accurate data to design from.

Re: Jagged contours from 1x1m .asc file

Fuscha — Wed, 13 Jun 2018 13:08:57 GMT

Yes but that data is already from a laserscan which is available from the whole state here, I just need to tell them which type of file that I want. Until now I mostly ordered 1m-contours but now I started to use .asc files because they are mored detailed (at least in flat areas), but as you can see it didn't work out that well 😄

Re: Jagged contours from 1x1m .asc file

codee — Wed, 13 Jun 2018 20:08:01 GMT

If this is LIDAR data you may be able to get in LAZ format and run it through RECAP to generate point cloud that civil 3d can use.

Re: Jagged contours from 1x1m .asc file

codee — Wed, 13 Jun 2018 20:43:38 GMT

I dont think anything is going to help the jaggedness of those contours since it looks like the data was crated in rows and columns. Your triangles are where data was sampled from. This triangles are going to make perfect triangulations when you generate a surface. This is what really accurate raster data looks like up close.

Re: Jagged contours from 1x1m .asc file

rl_jackson — Thu, 14 Jun 2018 01:32:15 GMT

I'd be curious to see the metadata or link to this data with 1m contours, as I see it the data that was provided is only good for doing 5m/25m contour intervals, and with the area that your getting that sounds completely plausible.

Re: Jagged contours from 1x1m .asc file

Fuscha — Thu, 14 Mar 2019 13:59:44 GMT

Ok now I have to come back one more time to this topic 🙂 since I have another project where I need the same data from the drone flight just on another location. The provider told me he can send me the 3D-data in those formats:

- ASCII

- 3D-Shape

- ESRI-SHAPE

- GEOTIFF

- LAS

- LAZ

Now I would like to know what you guys think gives me the smoothest result in Civil3D for my surface or if it's just the level of detail that causes the troubles...which would be bad since I often have a larger area (for example 500m x 500m) where I need pretty detailed surfaces.

Thanks, Tom!

Re: Jagged contours from 1x1m .asc file

Fuscha — Thu, 14 Mar 2019 14:57:01 GMT

Ok I just saw that answer with the LAZ data (sry I haven't been on the forum for a while) and googled a bit about it...seems like this will be a good possibility to try out!

Re: Jagged contours from 1x1m .asc file

ACADuser — Thu, 14 Mar 2019 16:19:43 GMT

Re: Jagged contours from 1x1m .asc file

tcorey — Thu, 14 Mar 2019 19:09:21 GMT

You mention above that you have Global Mapper.

Create contours there and then export to DXF. Import the DXF into Civil 3D. Make your Civil 3D surface from those polylines.

Re: Jagged contours from 1x1m .asc file

Fuscha — Thu, 04 Apr 2019 12:26:44 GMT

Ok once again I have to come back to this topic sry for that 😛

Now for my next project I ordered the laserscan data as .laz files. I imported them in recap and loaded the point cloud into civil3d, everything worked perfectly fine.

The only problem I have now is that the files seems to be way to big, as soon as i make a surface out of my point cloud the drawing gets extremely slow. I guess the problem is once again the amount of points...the point distance sometimes is <0,5m for an area with several 100m in size...

Now I wanted to ask if there are any possibilities to somehow "clean" my point cloud to lower the amount of points? All I could find is the option in recap for the decimation grid, but even 100mm setting doesn't really affect the cloud...

Maybe someone got an idea 🙂

Re: Jagged contours from 1x1m .asc file

rl_jackson — Thu, 04 Apr 2019 15:00:21 GMT

When you create the RCP, reduce the intensity to like 30% or even less (you could probably do 10%). The problem is its just far to much information than you'll never need or want in a real world solution. I've done land survey work on critical infrastructure (airport runway) and with conventional methods and the grid was 25' that worked just fine. LAS/LAZ and drone data in general is just too much information and completely necessary, I embrace the technology but, but the current methods of transferring the data to C3D IMO SUCK