Remove/edit surface triangle

[OliverE]

I've created a surface from contours that were exported from 12d. The contours all look fine from the export but when I create the surface and add the contours I get one random triangle the has an elevation of 300m or so below the rest. How can I eliminate this from happening during my surface definition/creation and/or how can I edit my surface to remove this one tiny section that is making my surface inaccurate. View my surface in the attached dwg using object viewer and you'll see what I mean. This happens quite often for me. I'm assuming it has something to do with crossing lines etc. The original contours are in the same drawing if you need to look at those too.

Thank you in advance,

Oliver

[Jeew-m · Accepted solution]

Hi,

If you know the general elevation range of the surface you can exclude other elevation through surface definition.

https://knowledge.autodesk.com/support/civil-3d/learn-explore/caas/CloudHelp/cloudhelp/2019/ENU/Civi...

Thanks

[Jeff_M · Accepted solution]

In addition to the suggestion by @Jeew-m you can also weed the contours when adding them. The existing polylines have a lot of vertices that aren't really needed for a good surface definition. I used both the weeding and the exclude elevation < 200 and got a good surface to build. 

[OliverE]

Great, thank you to both of you. Can you expand on the uses of the weeding factor? I can't remember what that setting changes.

Cheers.

[Jeff_M]

The Help file explains it quite well:

http://help.autodesk.com/view/CIV3D/2018/ENU/index.html?guid=GUID-523368FB-BF6D-4E7C-8E38-7BA9A2B7E3...

[OliverE]

Ya sorry should have checked that first. I've tried recreating the surface multiple times using the original contours and changing the weeding/supplementing factors as well as changing the exclude elevations ranges - I still get the 0 elevation most of the time. The only time I got the surface to show up without the 0 elevation was by changing the weed factor to 10000 and the supplementing factor to 10001 which is obviously not correct. Then when I tried to recreate the surface using those exact values and the same process, the 0 elevation showed up again....is it just C3D randomly messing up or is there potentially an error with the contours I was provided. Would it be better to use a exported triangles rather than contours?

Thanks

[Jeff_M · Accepted solution]

Rather than using the weeding in the Add Contours, try using Mapclean on the polylines first. It also has a Weed polylines, as well as many other options to cleanup the polylines. There is an option to either edit the original objects or create new ones. If you use the latter you will be able to see what the difference is between them. Using only Mapclean on your file, with the options set like so: 

and using the default settings resulted in creating a decent surface. Playing with the weeding factors would likely help to dial it in a bit more if desired.

[OliverE]

Thank you for 3 great suggestions. Just made my life much easier.