Reducing the number of points on a triangulated irregular network (TIN) surface

By Partha Sarkar

If you want to make Civil 3D TIN surface smaller and easier to process faster by reducing the number of points, what you do ?

In Civil 3D UI tools, you can select the Edits -> 'Simplify Surface…' option to bring up the "Simplify Surface – SurfaceName" dialog box and there in the "Reduction Options" you can specify the 'Percentage of points to remove' as shown in the picture below –

The same operation, you can perform by calling your custom command and invoking the TinSurface.SimplifySurface() function. Here is a C# .NET code snippet on the same :

using (Transaction trans = db.TransactionManager.StartTransaction())
{
    TinSurface surface = trans.GetObject(surfaceId, OpenMode.ForRead) as TinSurface;
 
    // SurfaceSimplifyOptions 
    // This class represents the options for simplifing a TinSurface object.
 
    SurfaceSimplifyOptions ssop = new SurfaceSimplifyOptions(SurfaceSimplifyType.PointRemoval);
    //specify the 'Percentage of points to remove'
    ssop.PercentageToRemove = 0.40;
 
    // Call SimplifySurface() now
    surface.SimplifySurface(ssop);
 
    // Rebuild the Surface
    surface.Rebuild();                
 
    trans.Commit();
}