MtoA supports Bifrost, a tool for creating simulated liquid and volume effects in Maya. When creating a Bifröst simulation system with Maya 2018.1[+] and Arnold 5 a new set of shading graphs are created for each system using some of Arnolds included shaders.
|Liquid (Standard Surface)||** Bifrost copy Hidden ** Foam(Standard Volume)** Bifrost copy Hidden **||Aero (Standard Volume)|
Renders as a Surface.
Surface Controls-> Surface Type - Mesh.
Renders as Points.
Point Control-> Type - Spheres.
Renders as a Volume.
Volume Controls-> Density Channel - Density.
Arnold allows for liquid to be rendered as a mesh or as an Implicit surface. Those attributes can be found in various tabs found in the liquidShape node under the Arnold tab.By default, a Standard Surface shader is assigned to a Bifröst liquid with the shader attributes tuned to simulate a deep water effect.
The rendered output of the liquid simulation can be controlled procedurally with the following attributes found under Liquid Shape-> Arnold->Surface Controls-> Mesh Controls :
Foam particles can be added to liquids to create bubbles, foam, and spray effects. These are rendered as points or spheres in MtoA which support motion blur. Per-particle attributes are exported as user data. The particle attributes are controlled by the native foam shader with ramps (diffuse, reflection, etc...). Foam can be treated either as volumetric spheres (with a volume shader ) (i.e. points with step_size) or points/spheres primitive (with a surface shader).
The volume controls can be found in the aeroShape node under the Arnold-> Volume Controls tab:
Using the Utility user data nodes, you can create a shading network in order to render out Bifröst channels.