I have a question

[Chippsetter2]

I have not used anything other than basic Autocad since Autocad 2008. Back then (2007-2008) it was Land Desktop, not Civil 3d. I now have Civil 3d 2011. My problem is that I can't seem to find how to sample the existing contours in the drawing to creat a surface in which I can build my new surface on.

[Matt.Anderson]

Back in 2008,  CIvil 3d was Civil 3d 2008 and Land Desktop 2008 is a completely different program.   Think Notepad vs Office Word.

You need to build a surface in Civil 3d. 

[Chippsetter2]

Then to build a surface do I need points first? If so I am out of luck as all I have are 3d contour lines. If I can use them what do I need to do? When I looked and the Autodesk information last year when I was with another company it stated that the Land Desktop abilities were merged into Civil 3d 2010.

[Sinc]

Not sure what you mean by "Land Desktop abilities were merged into Civil 3d 2010"...  Land Desktop and Civil 3D are two completely different programs.  Maybe you're referring to the fact that Land Desktop was discontinued with the 2009 version, and has been replaced by Civil 3D in Autodesk's product catalogue...?

You can create a C3D surface from contours.  Just add them to the surface definition.  If you haven't already, you should stop and do the tutorials that ship with the product; they explain this basic stuff in a moderately complete fashion.

Of course, ideally you would not build a surface from contours...  That's the most error-prone way possible to build a surface.  But you can do it, if it's your only choice.

[dgordon]

Chip,

We generally get field topo from our surveyors who give us a coordinate file with survey shot points.   We import these points into C3D using the fieldbook format and the survey database.   Once the points are in c3d, we weed out any shoots that aren't part of the ground surface like benchmark shots using a point group.   We then export the point group to a txt file in pnezd format.   Then we create a surface and give it a name like existing surface.   Then we expand the surface in the collection and goto add point file.   Any breaklines created by the surveyors are also added as breaklines.

each time you add data to the surface it will require a rebuild.   Either set it to automatic rebuild or manual.

if you have a vanilla autocad surface with 3d mesh, this will need to be converted to 3d faces.   Then the 3dfaces could be added by picking the option for autocad objects.

If the previous surface was created with land desktop, there is a migration tool to bring in land desktop surfaces.

Hope this helps,

Dan

[Chippsetter2]

I did not get any points or tin information. What we got from our client was this topo drawing from a surveyor they used, not from the one will will use when this design is ready to get closer to development. The project is a couple states away so the surveyor used was located there.Our surveyor will be surveying a much smaller area of this property and the stuff outside of what we need will not be critical to us as that development is handled by another firm. What I am trying to do now is make sure all my required earthwork will generally stay within the boundaries of our project and I can get the water draining correctly. I can do it in plain Autocad but takes longer.

[dgordon]

Chip,

Sometimes when we get surveys from a outside source, they contain 3d faces or survey points which are simply frozen inside the base drawing file.

use laythw and layon to see if this might be the case.  Have you tried asking the client for more useful information...i.e. landxml file, or coordinate file?

Well, like Sinc mentioned, if you have to, just add the contours to a surface using either the contours option or add the contours and breaklines.

Dan

[TonyLeggieri3279]

Chip,

To "sample" your existing contours into a surface, you need to open the Toolspace, right click on "Surfaces" in the Prospector, and choose "Create Surface...".  Fill in whatever info you need.

Once the surface is created, expand it in the Prospector, and expand the "Definition" section.  Right click on "contours" and choose "add".  This will allow you to add your contours to your surface.

The functionality of Land is virtually identical to Civil3D with the exception of you don't need to "sample" objects anymore.  Once you have added those contours to your surface, if you modify any of the contours in any way, your surface will automatically update (or prompt you that it needs updating).

You can add any feature you wish to a surface in that Definition section of the surface on the Prospector.

Tony