如果你需要更改曲面的样式，比如更改等高线的颜色等等，在Civil 3D中，你可以通过在toolspace中选中曲面，然后点右键选择“Edit surface style…”然后切换到“Display” tab 来更改，:

下面的通过代码的方式使用API来实现同样的效果:

[CommandMethod("MyGroup", "SurfaceStyleExample", 
    "SurfaceStyleExample", CommandFlags.Modal)]
public void MyCommand() // This method can have any name
{
 
    Document doc = Application.DocumentManager.MdiActiveDocument;
    
    if (doc != null)
    {
        Editor ed = Application.DocumentManager
            .MdiActiveDocument.Editor;

        

        // select a tin surface

        PromptEntityOptions peo = new PromptEntityOptions(
          "\nSelect a tin surface: ");
        peo.SetRejectMessage("\nOnly Tin surface is accepted");
        peo.AddAllowedClass(typeof(TinSurface), true);
        PromptEntityResult per = ed.GetEntity(peo);
        if (per.Status != PromptStatus.OK) return;

        CivilDocument civilDoc = CivilApplication.ActiveDocument;

        using (Transaction trans = doc.TransactionManager
            .StartTransaction())
        {
            TinSurface surface = trans.GetObject(per.ObjectId, 
                OpenMode.ForRead) as TinSurface;

            //exclude invalid points， 附赠功能，排除异常点

            surface.BuildOptions.ExecludeMaximumElevation = true;
            surface.BuildOptions.MaximumElevation = 5000;
            surface.BuildOptions.ExecludeMinimumElevation = true;
            surface.BuildOptions.MinimumElevation = 200;

            //set the Maximum Triangle Length，设置三角形最大边长

            surface.BuildOptions.MaximumTriangleLength = 200;

            //change the style， 下面开始更改样式了
            ObjectId styleId;
            if (civilDoc.Styles.SurfaceStyles.Contains("Standard"))
            {
                styleId = civilDoc.Styles.SurfaceStyles["Standard"];
            }
            else
            {
                // create a new style called 'example style':
                styleId = civilDoc.Styles.SurfaceStyles
                    .Add("example style");

            }
            
            

            // modify the style

            SurfaceStyle surfaceStyle = styleId.GetObject(
                OpenMode.ForWrite) as SurfaceStyle;

            //countours smoothing 

            surfaceStyle.ContourStyle.SmoothContours = true;
            surfaceStyle.ContourStyle.SmoothingType 
                = ContourSmoothingType.AddVertices;
            surfaceStyle.ContourStyle.SmoothingFactor = 10;

            surfaceStyle.ContourStyle.MajorContourColorScheme 
                = ColorSchemeType.Rainbow;

            //Major contour, red

            surfaceStyle.GetDisplayStylePlan(
                SurfaceDisplayStyleType.MajorContour).Color 
                = Autodesk.AutoCAD.Colors.Color.FromRgb(255, 0, 0);

            //Major contour, layer 0

            surfaceStyle.GetDisplayStylePlan(
                SurfaceDisplayStyleType.MajorContour).Layer = "0";

            //Mainor contour, gree

            surfaceStyle.GetDisplayStylePlan(
                SurfaceDisplayStyleType.MinorContour).Color 
                = Autodesk.AutoCAD.Colors.Color.FromRgb(0, 255, 0);

            //Mainor contour, layer 0， 如果你要放在其他图层，要确保该图层存在

            surfaceStyle.GetDisplayStylePlan(
                SurfaceDisplayStyleType.MajorContour).Layer = "0";

            // display major contours:

            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .MajorContour).Visible = true;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .MinorContour).Visible = true;

            // turn off display of other items:
            
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .UserContours).Visible = false;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .Directions).Visible = false;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .Elevations).Visible = false;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .Slopes).Visible = false;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .SlopeArrows).Visible = false;
            surfaceStyle.GetDisplayStylePlan(SurfaceDisplayStyleType
                .Watersheds).Visible = false;

            //TODO: do the same for all model display settings as well
            // 

            // assign the style to the first surface in the document:
           
            surface.StyleId = styleId;

            // commit the transaction

            trans.Commit();

            //rebuild the surface 
            surface.Rebuild();
        }

    }

}

改之前的样子:

运行之后，等高线的颜色已经改变了.

Hope this helps.