Hello,
I am using Civil 3D 2014.
I have recieved existing contours from my surveyor and added them to an existing grade surface, using 5-feet supplementing factor and 0.10 mid ordinate distance, when added as "breaklines". I have also added them as "contours" without any visible difference. However, I notice that in a few places, the surface does not appear to triangulate to the contours (see attached image). It appears this may be a limitation working with contour surface data, perhaps we should be using tinn triangles from surveyour and not contours? Any suggestions?
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What flattening options are you using when you add the contours to the surface? That makes a huge difference.
Would your surveyor be willing to provide you with triangles? (A C3D surface would be the best but take what you can get)
Don Ireland
Engineering Design Technician
I believe the surveyor will provide what is requested for the most part. I just need to confirm what is the best data to request. Would triangles trump contours? How about LandXML, is that even better?
The best would be the dwg file with the surface in it then Points & Breaklines, then triangles. Then somewhere down the list would be contours.
Contours are an interpolation of the triangles.
Think of it like getting data from someone and they've rounded everything to 1 decimal place and you want to add their data to yours which is accurate to 4 decimal places. Their data is rounded off (interpolated).
Don Ireland
Engineering Design Technician
For a great explanation of what I mean, watch this video from AU2013 (from around 8:30 or so for about 4-5 min). It's talking about taking survey data from C3D to revit. But the reason I would not want to import contours into C3D is the same.
http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2013/revit-for-architects/ci3206
These guys do a great job of explaining the issue.
EDIT: If you watch it long enough, you'll see why I say I'd want the breaklines too.
Don Ireland
Engineering Design Technician
TCorey,
I have attached my flattening options, at least the ones I am familiar with. If they should have different defaults, what should they be set to?
I would decrease the supplementing distance/angle values so that Civil 3D adds points where those triangular shapes are showing up, then it can apply its contour optimization settings because there will be points for it to process.
neilyj (No connection with Autodesk other than using the products in the real world)
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You are probably already all set here, but if you can't get the surveyors C3D surface you want to receive the TIN lines and the borders.
In C3D when you create your surface by importing 3D Faces (TIN Triangles from C3D) or importing Lines (the TIN lines from LDD) make sure you have the "Maintain Edges From Objects" checked on. Otherwise the TIN can retriangulate on you and will not agree with edits the surveyor has made. Save smoothing, whatever your prefered method, these contours should all agree very closely, and the data between contours, as Doni pointed out, will be correct all the way around.
Then you can add any outer and hide borders.
LandXML is good, but also has the ability to re-triangulate on you if not exported correctly/completely, no matter what you do on your end to make sure that doesn't happen.