The Atmospheric class lets you set up volumetric rendering effects with the scripter. You can create atmospherics like combustion and fog, access various properties on them and maintain their gizmo list of nodes such as lights and atmospheric helpers.
You can determine what atmospherics are available using the showclass function as follows:
showclass "*:atmospheric.*"
This displays all the atmospheric classes and the properties accessible on each.
Atmospherics have several common properties and methods:
<atmos>.name : string, the name as it appears in the env. dialog list
<atmos>.numGizmos : integer, readonly
getGizmo <atmos> <index>
retrieves the indexed gizmo node from the atmospheric, a light or atmospheric helper, for example. Index is 1-based.
deleteGizmo <atmos> <index>
deletes the indexed gizmo from the atmospheric
appendGizmo <atmos> <node>
appends the node to the gizmo list on the atmospheric. It must be of the right kind for the atmospheric, lights for volumeLights, helper gizmos for combust, etc.
atmos = combust density:20 outer_color:red
appendGizmo atmos $SphereGizmo01