1.6.3. SoHeightFieldProperty

The SoHeightFieldProperty⁽^C++^|^Java^|^.NET⁾ node is also analogous to (and derived from) SoVolumeData⁽^C++^|^Java^|^.NET⁾. This node defines a set of values on a uniform grid in the XY plane that can be used to color the height field defined by an SoHeightFieldGeometry⁽^C++^|^Java^|^.NET⁾ node when rendered using an SoHeightFieldRender⁽^C++^|^Java^|^.NET⁾ node. Similar to SoHeightFieldGeometry⁽^C++^|^Java^|^.NET⁾, a height field property data set is a volume, whose Z dimension must be 1. The volume can be loaded using any of the usual mechanisms.

An SoHeightFieldProperty⁽^C++^|^Java^|^.NET⁾ node is not required to render a height field. If there is no property associated with the height field, it will be rendered using the current material (see SoMaterial⁽^C++^|^Java^|^.NET⁾) like any other geometry. If you want to map the height values themselves to colors, create an SoHeightFieldProperty⁽^C++^|^Java^|^.NET⁾ node and set its volume to the same values as the SoHeightFieldGeometry⁽^C++^|^Java^|^.NET⁾ node. For example, if the height values are loaded from a data file on disk, simply set the fileName field to the same string as the SoHeightFieldGeometry⁽^C++^|^Java^|^.NET⁾ node.

Typically the property volume will contain scalar values and those values will be mapped to colors using the current data range (see SoDataRange⁽^C++^|^Java^|^.NET⁾) and color map (see SoTransferFunction⁽^C++^|^Java^|^.NET⁾). However the property volume may contain RGBA values, for example aerial imagery to be draped over terrain.

Figure 1.86. No property	Figure 1.87. Property = height values	Figure 1.88. Property = RGBA image
Terrain (LIDAR) data

Multiple SoHeightFieldProperty⁽^C++^|^Java^|^.NET⁾ nodes can be inserted in a scene graph and combined together in the GPU to do render compositing. However the default fragment shader only handles one property (the first one). To combine multiple properties use a custom shader program (see SoVolumeShader⁽^C++^|^Java^|^.NET⁾ and Section 1.8, “Shaders”).

It is not necessary (or useful) to set the extent field. SoHeightFieldRender⁽^C++^|^Java^|^.NET⁾ will automatically use the extent associated with the SoHeightFieldGeometry⁽^C++^|^Java^|^.NET⁾ node.

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