I've brought in a raster elevation file and have created a contour layer and I now want to use the contours in Civil 3D. I have done this several months ago but can't remember how I did it but I seem to remember it took several steps
Can anyone remind me how to do this?
Solved! Go to Solution.
first step is to use _MAPIMPORT to import the polylines and the objectdata (especially the field ELEVATION).
Save this drawing, close it. Create a new drawing and use command _ADEDRAWINGS and assign the previous dwg now.
Start command _ADEQUERY and query the entities with the option "CHANGE PROPERTIES" (hope this is called so in the English version) and define the elevation of the polyline that is created has to be overridden from the object-data field ELEVATION.
HTH, - alfred -
Once you created the SDF of the contours you can convert it to shp and use the Surface from GIS tools in Civil3d. You may need to do a little contour smoothing on the lines.
Thanks to both of you - worked like a charm.
I have a question though:
I used a raster level grid with a 50m spacing and using MAP and contour layers the contours at 1m spacing were pretty smooth and looked "good" but when I created a surface in CIVIL using the same raster data the contours were dreadful with 90 degree bends etc. Any idea why this should be the case?
This is why I wanted to use the MAP method - not bothered if the contours aren't a perfect reflection of the ground but they must look correct.
>> [...] 90 degree bends [...] Any idea why this should be the case?
Because Civil imports first the points and as the pixels in the raster a rectangular you'll get contours with 90 degree.
And as long as you don't want to run methods like smooth surface (which creates surfaces different to the dem, but smoother or "more beautiful contours then") I guess there are not to many ways to avoid that.
As you tried both ways it would be interesting to have both contour-results shown concurrently to compare them and so to see if Map3D/FDO has the better algorithm or is more away from reality
- alfred -
The Red contours are derived via MAP and the Grey via Civil 3D - both used the same source files.
The MAP version is certainly more pleasing to the eye... and for my purposes is a better one to use.
A full topo survey will need to be done eventually for detailed design work but this is ok for now
>> The MAP version is certainly more pleasing to the eye
Yep, and only for the eye
Looking to that area and the marked contour:
You'll recognize that this red contour crosses 3 Civil3D contours. As I assume that Civil3D really evaluates every single rasterpoint for creating the contour (and therefor generates 90°-corners sometimes) my feeling is that Map3D does contour-generalization with really big tolerance values.
So don't forget to put the info about data source (and generalization of contours) into the description area of the surface-properties. At least that is my way to save the info so everyone looking to this surfaces (now or years later) knows how to interpret it's quality.
Thx for the screenshot, I have not yet verified that in detail
- alfred -
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