The set_viewport_volume_settings node lets you control the quality and speed of NanoVTT rendering of volumes in the viewports. NanoVTT renders volumes in the viewport that closely match Arnold renderings, with support for colored volumes and physically-based thermodynamic emission scaling. In addition, viewport volumes are rendered with an alpha channel, which is useful for playblasts that can be composited.
To use set_viewport_volume_settings, connect the volume to be rendered into the volume input and then connect the out_volume output to a graph output or terminal node. When mode is set to NanoVTT, you can adjust the quality, interactive quality, and other settings.
In particular if you get timeout detection and recovery (TDR) errors on your graphics card, you should reduce the quality settings.
When mode is set to Legacy Volume, volumes are rendered in the viewport using the old shader. The quality and other settings in the set_viewport_volume_settings node are not used by this shader.