VolumeViz Basics

Just like core Open Inventor, VolumeViz can be considered to have data nodes, property nodes and geometry (rendering) nodes. What you already know about using nodes, fields, actions and so on also applies to VolumeViz! There are some small differences that we will highlight in this chapter.

A basic VolumeViz scene graph is shown here:

A basic VolumeViz scene graph consists of:

• Data node: SoVolumeData

Note that unlike most Open Inventor data nodes, the actual volume data is not part of the scene graph and is not written to a .iv file. The SoVolumeData node is just a reference to the actual data, which typically exists in a format specific data file.

• Property nodes, for example:

+ **SoMaterial** : Specifies the base color and opacity for voxels in the volume.
+ **SoTransferFunction** : The “color map”, specifies the mapping from scalar data values to RGBA color values.
+ **SoDataRange** : Specifies the range of scalar data values to be mapped into the color map.

• Render (geometry) node, for example:

+ **SoOrthoSlice** : Renders an axis-aligned slice.
+ **SoVolumeSkin** : Renders an opaque subvolume