The SoOffscreenVolumeRender node extracts data by rendering one or multiple volumes (via SoVolumeRender) into a buffer that can then be used in various computations tasks.
To implement an extraction, the application must derive a new class from SoOffscreenVolumeRender and implement the boxComputed and the getNextSubBox methods.
SoVolumeData, SoVolumeRender, SoOffscreenVolumeRender