Autodesk civil - import contours.

[therock005]

I create a surface in which i want to define via the contours that my drawing has, but i dont understand the options.It says weeding factors and supplemental factors,and it asks for some distances and an angle even.

What should i fill in these boxes do i can import me contours?

[eldon]

AutoCAD can only handle straight lines when it forms a ground surface. If you are inputting contours which are curved, there must be a transformation of the curves to straight lines.

If you check in the HELP section under Contour Weeding Dialog Box, you will see all sorts of helpful diagrams to explain the various technical terms.

[therock005]

Thanx for pointing it out havent noticed the diagrams on the help,but its crazy,y isnt it more automated?

There are polylines with an elevation,whats that difficult for it to handle and it need a manual touch?

[rustysilo]

When it builds the TIN from contours it connects the vertices of the contour lines. The weeding factor "weeds out" vertices while supplementing "supplements" or "adds" vertices. The help file should describe it fairly well.

Alternatively you could place points along your contours (there is a tool to do this at a given distance or per the vertices) and build the surface from those points.

Here is a section in the Civil 3D help file that may further help you in this department:

Supplementing Missing Contour Information
When you create a model from contours and then generate contours from this model, in some cases, AutoCAD Civil 3D may not generate the same set of contours.
In the most common situation, surface data is missing in either a low or high area, such as near the top of a hill, at the bottom of a valley, or on the edge of the site.
To correct this problem, place spot elevations or another contour line near the place where the surface data is missing. For example, if a contour line is missing along the top of a hill, place a new contour, breakline, or spot elevation at the estimated maximum elevation of the hill. It is recommended that you place any interpolated data, points, or contours on a separate layer.
If you create a surface using only contour information, you may need to place breaklines or spot elevations in areas where the contour line changes direction drastically. Areas where this is likely to happen include: a crowned roadway, a swale, or a ridge. In these places, contours might tend to triangulate onto themselves. In most instances, the Minimizing Flat Areas operation resolves this problem. For more information, see Minimizing Flat Areas. In extremely severe situations, you may need to add additional point or breakline data.
For best results, always follow the suggested the order of operations for adding contour data to a surface. For more information, see Recommendations for Creating Surfaces from Contours.

[therock005]

I dont have any data to work with,i just have a cad file where rd polylines act as contour.

And bu using supplementing and weeding factors the contous generated are a mess and do not represent the initial contours at all,not even close!

I really dont understand y it needs to add and remove vertices...

[rustysilo]

What are you using for your weeding and supplementing factors?

Are you adding polyline contours as breaklines or as contour data to your surface?

Can you post your file, or at least a graphic of the original and the resulting contours?

[therock005]

No i'm adding them as contour data.I tried the diffult,i think 1 as distance and 4 degree angle if i'm not mistaken.

Yes of course,here is the file.Sorry but it was more than the allowed size for attachment and i had to upload it somewhere

http://rapidshare.com/files/80952143...-file.dwg.html

[rustysilo]

I used weeding factor of 1 and supplementing of 5 and they are close. The differences can probably be ironed out by swapping edges in the surface.

[therock005]

Are you sure?Cause it's justnot happening for me.Are you importing as countour data?

If i import as contour data and select everything in the drawing,then something happens but result is a mess.

If i on the other hand isolate the contour layers and i select the contours,then event viewer pops up displaying a thousand messages about breakline not added-crossing breakline.

If i try importing breaklines as well,then i get like 5000 messages of breaklines not added.and finally nothing shows up,no borders,no major/minor contour,nada.

[therock005]

Ok so i played around with it and i got it to work but it does so only for the major contours!(The red ones in the drawing).It displays most of them as minor and a couple as major,and no real minor contour is generated.

Any thoughts?