Built by Proximity

I would like to share some tips that I use to build a good surface model.  This, like a good foundation, keeps everything else STABLE. Without a good surface model, the rest of the engineering that we do can get shaky.

As the title indicates – proximity breaklines is an issue many people struggle with.

Proximity Breaklines are probably the most abused and least understood breakline in the arsenal of surface tools.  The definition that I like the best is in the AutoCAD Civil 3d 2009 Developers Guide on page 52.

A proximity breakline does not add new points to a surface. Instead, the nearest surface point to each breakline endpoint is used.”

Before Proximity 

In this image, we have surface across the driveway entrance.  However, the gutter flow across that entrance isn’t correctly modeled.  This is a perfect example of where to add a proximity breakline (shown in red above).  When you draw the line selected in the image below, your triangle faces correct nicely.

After Proximity

Be sure to use save your surface style set correctly, and you can delete what really is a sloppy line because the computer actually redrew your line between the points and that data is now part of the surface.

Style Setting

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