The
bifrostAeroMaterial is a mental ray material that gets applied automatically to the
aero and
bifrostAeroMesh objects when you create a Bifröst simulation. It is a volume ray marcher that accumulates the shading contributions from emission, absorption, and scattering at each step, based on the density. See
Render a Bifröst simulation.
Tip: For faster but less accurate rendering, especially when tweaking settings, you can adjust the attributes in the
mental ray block. For example, you can reduce the
Max Steps values and increase the
Step Size values.
Density
-
Scale
- Provides overall control over the strength of the shader's effect, including the contributions from the individual emission, absorption, and scattering components.
-
Threshold
- A minimum value of density, below which the shader has no effect.
-
Density Remap
- Allows you to select an existing channel defined on the Bifröst shape or mesh to drive the density. When this is set to a value other than
None, you can expand the
Density Remap group to define a value ramp based on the channel values.
Common Attributes
The
Emission,
Absorption, and
Scattering attribute blocks contain several attributes in common, which work in the same way.
-
Color
- The color of the shading component.
-
Intensity
- Controls the relative strength of the individual shading components independently.
-
Offset
- Biases the falloff of the shading component's intensity relative to the density. High values spread the region of high intensity over a wider range, resulting in a narrow falloff region near the edges, while low values restrict the region of high intensity to a smaller radius near the center.
Emission
Adds a constant color, as if the material was emitting light.
Note: Intensity Units are not implemented. There is no way to enable this attribute.
-
Color Remap Channel
- Allows you to select an existing channel defined on the Bifröst shape or mesh to drive the emission color. 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.
Absorption
Removes color from light that is transmitted through the material from behind. In addition to darkening, this can also change the hue and saturation.
-
Shadow Opacity Scale
- Controls the strength of shadows.
-
Colored Opacity
- Controls the saturation of the color that is absorbed, as well as cast as shadows.
Scattering
Scatters light that enters the volume.
-
Density Cutoff
- A minimum value of density, below which no scattering occurs.
-
Directionality
- Controls the proportion of back and forward scattering. At 0.0, there are equal amounts of back and forward scattering. At values closer to 1.0, more light gets scattered forward than back, emulating larger particulates such as smoke or dust.