Surface from Civil 3d contours

[jmoore.136085]

I can't use contours created by Civil 3d as part of the definition for a new surface.
Is this possiable ???
Thanks John

Thanks Harold and Brian
I understand contours not best data to build a surface from.
In my case I have surface of over 3 sg.km built using Lidar point files and a field survey of a corridor cutting through the site. So I want to use the Lidar points surface outside the surveyed corridor and the more precise field surevy data along the corridor to produce a single homogenious surface.
I will try the "extract objects" command
Thanks
again
John

[Harold Pei Jr]

Let me guess, they took you from LDD to Civil 3D without giving you any training?
The contours that you see are just a representation of the surface, not the true surface itself.
What would you want to use the contours of the surface for? Maybe if you let us know that much, we can point you in the right direction.

[brian.hailey933139]

Well, yes and no.

No because there are no contours in your drawing. If you select the contour, you select the surface, not a contour.

Yes because you can extract contours from the surface (Surfaces->Utilities->Extract Objects or something like that) and then use those to create a surface. Be warned, if you do that, you will not have a dynamic link back to the original surface.

Just out of curiosity, why are you trying to do this? Creating a surface from contours is not a very accurate way of creating a surface.

edit: Dang it! Harold beat me by one minute.

[Harold Pei Jr]

:mrgreen: it was pure luck.

[MattAnderson]

John -

Am I assuming that your field survey of the corridor is your Civil 3d surface? Try this - create a LIDAR surface - ignore the field survey.
Use the PASTE command to paste the LIDAR surface into a combined surface and then PASTE your field survey surface over the top. This combines the surfaces using surface data, and you don't need to have odd boundaries.

Matthew Anderson, PE
Joseph A Schudt & Associates

[jmoore.136085]

Thanks Matt
My issue is that I don't want the Lidar data to influence the surface along the corridor where we have more precise survey data.
The combined surface will be using all data, including the less precise Lidar data that I don't want along the surveyed corridor, will it not ??
Thanks
John

[Harold Pei Jr]

The order you paste the surfaces into that third "surface" affects how your surface comes out.
The order that Matt has it, the surveyed surface will go over your LiDAR surface, so in essence, your surveyed surface will be the one that changes the LiDAR where ever it is your corridor is.

[wag24]

I'm in Civil 3d 09. Is anyone having problems with crashing / surfaces disappearing?