Carrara has volumetric clouds that can be rendered in Octane 3.0. The plugin cannot gain direct access to the volumetric data held within Carrara but it can resample the volume. The default resample size is 100 * 100 * 100 but you can change this using the Octane Cloud effect.
Rendering clouds in Octane is disabled by default so you need to visit each cloud instance and select Enable in the Octane Cloud effect.
You can also assign an Octane Medium shader to a cloud instance. This will allow you to change the AbsorptionDefines how fast light is absorbed while passing through a medium., ScatteringDefines how fast light gets scattered when traveling through the medium., and Emission of the rendered cloud. This is done through the standard Carrara shader mechanism. The Carrara native renderer does not use shaders for Volumetric Clouds but you can assign one anyway and Octane will use it if you make it an Octane Medium shader.
Note that only the ‘new’ Carrara volumetric clouds are supported. The ‘old’ volumetric clouds, clouds, fire, fountain, and fog do not expose any volumetric data so they are not supported.