I do a lot of hydraulic modeling and create river bed surface datafrom surveyed points. I need to be able to transfer the surface data from Civil3D to GIS effectively. The issue is that GIS does not maintain the fidelity of my surface based on the breaklines I've drawn. It triangulates based on vertices and often triangulates through the feature lines. In LDD, I was able to do address this by adding vertices to my 3D polylines in a batch-type function. That is, I could select all of my 3D polylines and add vertices to them at the same time. In Civil3D, I have to add vertices to each feature line individually.
Does anyone know of a way to add vertices to feature lines, or to a surface, in a more efficient manner that maintains fidelity of surface data in the transfer from Civil3D to GIS?
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Have you looked into Project River Analysis for your River Hydraulic Modeling?
On your original questions - you could always "smooth" your surface, and then reproject your breaklines onto the surface to add additional verticies.
Can you export the triangles (I'm not particularly familiar with GIS but this is a fairly foolproof way of maintaining the fidelity of the surface)
Thanks, but GIS still only looks at the triangle vertices and doesn't understand the breaklines. I might have come up with a work-around though. I exported the triangles as a polygon shapefile, then converted it to a polyline shape and then used the ETGeowizards tools in GIS to densify the polylines to a 1' vertex spacing so that GIS will hopefully have difficulty interpolating through the triangle sides. This seems to have given satisfactory results and is not too lengthy a process.
Check out the AU class from 2010 CV231-1 Slope stability analysis wih Civil 3d by Donal McMoreland where he extracts surfaces to GIS (I'm working through it at the moment) that may help you a bit. I'm no GIS guru so don't know whether it will or not
What type of GIS analysis are you preparing?
btw - Project River Analysis is a free download here: http://labs.autodesk.com/utilities/civil3d_river/
What type of GIS program, E$SRI is only one there are many out there that work as well or better that handle DEM/TIN data differently.
Thanks again for the modeling info. I'm not doing much of an analysis in GIS. Simply getting my surface data for the channel of a river pasted into a monster LiDAR surface and then exporting those points to a 2D hydraulic model. GIS handles the large point files better and it's the platform that everyone else in my office uses. In addition, point export functions in GIS seem to have more options for adjusting density. I did try using a point cloud to make a LiDAR surface and that worked OK, but in this case there are more heavy surfaces that are involved that are already processed in GIS, so it makes sense for me to transfer the TIN to GIS. Also, the surface created in the 2D model will bear more resemblance to the GIS surface in terms of how it triangulates data, so viewing and manipulating surfaces in GIS prior to incorporating in a model makes sense.
Breaklines can be added to the surface in GIS - you'll just have to bring them in.
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