The surface series filling is controlled by the Fill and FillMode properties. The Fill property controls the transparency and material properties of the surface, and optionally the filling in case the FIllMode is set to Uniform. Below is a table enumerating the FillMode property's available options:

The following code snippet shows how to modify the FillMode property to achieve different filling types:

// surface filling with white to black palette
surface.FillMode = ENSurfaceFillMode.Zone;
surface.Palette = new NTwoColorPalette(NColor.White, NColor.Black);
// uniform surface filling
surface.FillMode = ENSurfaceFillMode.Uniform;
surface.Fill = new NColorFill(NColor.Blue);
// surface filling with custom colors.
surface.FillMode = ENSurfaceFillMode.CustomColors;
surface.Data.HasColor = true;

The surface also supports several frame modes that you can combine with the surface filling. The following table lists the available options:

ENSurfaceFrameMode	Description
None	The surface does not display a frame.
Mesh	The surface displays lines that connect adjacent data points. This frame type allows you to visualize the triangular network that connects the data points of the surface. The following picture shows a surface with a Mesh frame:
Contour	The surface displays contour lines at the elevations specified by the Palette object attached to the surface. The following picture shows a surface with a Contour frame:
MeshContour	The surface displays both mesh and contour lines. The following picture shows a surface with mesh and contour lines:
Dots	The surface displays dots at the positions of each data point in the surface. The following picture shows a surface that displays dots at the data point's positions:

The code snippet below shows how to modify the FrameMode property:

surface.FrameMode = ENSurfaceFrameMode.Contour;

The surface frame lines or dots (depending on the current FrameMode) are colored depending on the value of the FrameColorMode property that accepts values from the ENSurfaceFrameColorMode enumeration. The following table lists the available options:

// applies palette colors to the surface frame
surface.FrameColorMode = ENSurfaceFrameColorMode.Zone;

Surface series support flat and smooth shading modes that affect the surface appearance when lighting effects are turned on. When using smooth shading (also known as Gouraud shading), the surface calculates the color intensity at each vertex of the triangular mesh and then interpolates these colors across the triangle's surface. In contrast, flat shading assigns a single color to each triangle face, which results in a more faceted appearance. The shading mode is controlled by the ShadingMode property that accepts values from the ENShadingMode enumeration. By default, the shading mode is set to ENShadingMode.Flat, because it is less computationally expensive and results in faster surface series rendering. 

The following code shows how to modify the ShadingMode property:

surface.ShadingMode = ENShadingMode.Smooth;

The surface series has an attached palette object that defines the colors for the surface filling (when SurfaceFillStyle.Zone is used) as well as the colors for the surface frame (when the FrameColorMode property is set to ENSurfaceFrameColorMode.Zone). This object is accessible from the surface series Palette property. The following code shows how to create a palette with 4 zones:

surface.Palette = new NNFixedMulticolorPalette(new NColor[] {
                NColor.Red,
                NColor.Orange,
                NColor.Yellow,
                NColor.LightGreen });

The surface series can be displayed at a fixed elevation (flat contour surface chart). This is enabled by setting the DrawFlat property of the series to true. When this mode is enabled the vertical position of the surface is controlled from the FlatPositionMode and FlatPosition properties. The former accepts values from the ENSurfaceFlatPositionMode enumeration:

In addition to the automatically generated contour lines when the FrameMode is set to ENSurfaceFrameMode.Contour the surface series can also display contour lines at custom specified elevation, and with controllable stroke. This is achieved by adding objects of type NContourLine to the ContourLines collection of the series. The following code shows how to create a custom contour line and specify its value and stroke:

NContourLine contourLine = new NContourLine();
contourLine.Value = 100;
contourLine.Stroke = new NStroke(2.0f, NColor.Red);
surface.ContourLines.Add(contourLine);

The surface series by default will use a combination of CPU / GPU rendering, where some of the calculations are performed by the CPU and others are done on the GPU. The advantage of this approach is that computations that can be executed only once are done on the CPU and all the rest is performed on the GPU. In some cases, however, for example, when you have large dynamically changing data set in real time it is better to perform all calculations on the GPU. To enable this feature you need to set the EnableShaderRendering property to true:

surface.EnableShaderRendering = true;

A mesh and grid surface series represent data as a grid where each cell is defined by four neighboring data points which form a rectangle. To visualize the surface each grid cell is split into two adjacent triangles. This can be done in two alternative ways, depending on which pairs of opposing points in the cell are connected with a diagonal. The selection of a diagonal is called cell triangulation. The mesh and grid surface series support several modes for cell triangulation, and the currently used one is specified with the CellTriangulationMode property accepting values from the ENSurfaceCellTriangulationMode enumeration.  

The default mode is ENSurfaceCellTriangulationMode.MaxSum, which means that the points with the maximum sum of the elevations are connected with a diagonal. The triangulation mode can be controlled through the CellTriangulationMode property. It accepts values from the ENSurfaceCellTriangulationMode enumeration:

The following code sets how to set the CellTriangulationMode property:

gridSurface.CellTriangulationMode = ENSurfaceCellTriangulationMode.MinSum;

The surface series supports the following formatting commands for the legend item texts:

<zone_value> - palette value (for smooth palette only)
<zone_begin> - begin value of a zone (the lower value)
<zone_end> - second value of a zone (the higher value)

The following formatting commands are supported for the tooltip texts:

<value> - elevation value of a data point
<index> - index of a surface segment
<xindex> - x index of a surface segment
<zindex> - z index of a surface segment

The formatting properties for all elevation values can be controlled through the ValueFormatter property.

Charts

Cartesian