Surface from Contour Polylines: rugged by contours mismatching and overlapping

[Anonymous]

Hello Civil 3D Professionals,

I started using AutoCAD Civil extensively last 2 months. I have been creating surfaces using points and using contour polylines.

My colleage provided me with  AutoCAD Contour polylines from seperate files. We are developing a topography using the most correct terrain by cutting and pasting the contour polylines.  I needed to create topography using this patched up contour map.

Origionally, I took the point creation and point grouping route to create surface but the file was well over 200MB and it is not even workable due to several hundred thousand points.

So, I tired using contour lines as the drawing data for the surface. So far, I manage to keep the files less than 10 MB but the terrain in the valley is so rugged due to several overlapping areas in the patched up contour data. How can I fix this?

I need to fix this until I can show my boss a topo with a smooth surfe without the disproportioned tiangulation.

Thank you for viewing this. I am really in need of help and guidance.

Sincerely,

Kyaw

[AllenJessup · Accepted solution]

Hello Kyaw and welcome to the forums.

Looking at only the Surface doesn't tell me much. The only suggestion I can make it to try using the polylines as Breaklines instead of Contours. If you have overlapping areas they will probably have to be cleaned up manually.

[neilyj666 · Accepted solution]

Unfortunately contour polylines are probaly the worst possible choice of object with which to build a surface as they tend to have many vertices. Unless they are very closely spaced in terms of vertical spacing then the surface is very questionable (but depends on the end use).

Contours can be used but ensure all options are ticked when building the surface and amend the supplementing factors to get the best possible surface with these objects