bifrostLiquidMaterial

Depending on your renderer, the bifrostLiquidMaterial might get applied automatically to the liquid and bifrostLiquidMesh objects when you create a Bifröst simulation. Some renderers can use it to render the isosurface (level set) of the voxels directly, in addition to the generated mesh.

Note: Consult the documentation for your renderer for information about whether this shader or all of its attributes are supported. The Maya Software, Maya Hardware, and Maya Vector renderers do not support this shader at all. The Maya Hardware 2.0 renderer supports some attributes.

Common Attributes

The Reflection, Refraction/Transmission, Surface Foam, and Diffuse attribute blocks contain many parameters in common. They all work in the same way, but control different layers.

Color
The color of the layer, if Color Remap Channel is set to None.
Color Remap Channel
Allows you to select an existing channel defined on the Bifröst shape or mesh to drive the color of the layer. When this is set to a value other than None, you can expand the associated Color Remap group to define a color ramp based on the channel values.
Weight
The scalar weight of the layer, if Color Remap Channel is set to None. This controls the strength of the layer as well as the amount of light energy that reaches the next layer.

For the Reflection layer, the final weight is also affected by the incidence angle (controlled by either the Fresnel or custom controls).

Weight Remap Channel
Allows you to select an existing channel defined on the Bifröst shape or mesh to drive the weight of the layer. When this is set to a value other than None, you can expand the associated Weight Remap group to define a value ramp based on the channel values.

Reflection

Controls the glossy reflection layer.

Roughness
The roughness of the surface causing glossy reflections. A value of 0.0 is smooth like a mirror, and a value of 1.0 reflects in a hemisphere like a diffuse material. In between 0.0 and 1.0, the material reflects in a narrow (low roughness) or wide (high roughness) cone.

Fresnel

Index of Refraction
The index of refraction used to calculate the final weight of the reflection layer.
Use Fresnel Reflection
Switches between a Fresnel and custom layer for glossy reflection.
  • When this option is on, the final weight is based on the Fresnel equation and the Index of Refraction. This is typically used for dielectric materials such as water and glass.
  • When this option is off, the final weight is based on the custom 0 Degree Reflection, 90 Degree Reflection, and Curve Exponent values. This is typically used for metallic and hybrid materials.
0 Degree Reflection
The reflectivity for surfaces directly facing the camera. Metals have high values (0.8 — 1.0), while layered materials like linoleum or lacquered wood have smaller values (0.1 — 0.3).
90 Degree Reflection
The reflectivity for surfaces perpendicular to the camera. This can be set at 1.0 for most materials.
Curve Exponent
Controls the exponent of the falloff curve used to interpolate between 0 Degree Reflection and 90 Degree Reflection.

Refraction/Transmission

Controls the amount of light that is transmitted through the material, and how that light gets bent.

Index of Refraction
The index of refraction used to control the bending of transmitted light rays.
Roughness
The roughness of the surface glossy transmission. A value of 0.0 is smooth like polished glass, while higher values disperse the light to cause a translucent effect.
Use Color at Max Distance
Limits the length of refracted rays. This can be used for performance or effect. When this option is on, refracted rays fade to the specified color over Max Distance. This can be used to emulate an absorbing medium.
Max Distance
The distance to use with Use Color at Max Distance.
Transparency
The weight of the refractive/transmissive layer.

Surface Foam

Controls an extra diffuse layer that can be used to emulate partially opaque materials. Typically, you would drive the weight using the Bifröst velocity or vorticity channels to simulate churning whitewater.

Diffuse

Controls the bottom-most, diffuse-only layer.