The settings of the Corona FumeFX Modifier are similar to those available in the Corona Volume Grid object.
Shading
Emission
Checkbox– Enables emissions in this volume.
Channel– Selects the channel that is used as a source for medium emission. Along with channels (grids) presented in the FumeFX object, such as Temperature, Density, Velocity, etc., a special option can be selected:
Constant – Contains only the value 1, which fills the whole bounding box of the volume grid.
Tint– Enables modulation of the final color by texmap. Only Object XYZ and World XYZ mapping are supported.
Mode– Defines the way in which data in the selected emission channel is mapped to the final emission of the volume.
Raw data – Channel data are not mapped and are only influenced by scale and tint. Channel mapping – Emission channel undergoes mapping to colors, which is accessible under the "Channel color mapping" button. Blackbody – Emission channel is treated as temperature in Kelvins and converted to color according to blackbody radiation laws.
Scale–Uniformly scales emission amount after mapping.
Temperature scale– If emission mode is set to Blackbody, the selected emission channel is treated as temperature in Kelvin and these parameters are used to linearly scale the temperature.
Channel color mapping– Opens the Channel color mapping window, where you can choose how values from the selected channel are mapped to colors.
Absorption
Checkbox – Enables absorption in this volume.
Channel– Еnables absorption in this volume. Selects the channel that is used as a source for absorption. Along with channels (grids) presented in the FumeFX object, a special option can be selected:
Constant– Contains only the value 1, which fills the whole bounding box of the volume grid.
Tint– Enables modulation of the final color by texmap. Only Object XYZ and World XYZ mapping are supported.
Scale – Uniformly scales absorption amount after channel mapping.
Channel color mapping – Opens the Channel color mapping window, where you can choose how values from the selected channel are mapped to colors. Use the checkbox to enable mapping of channel value to colors. If mapping is switched off, float channel values are treated as luminance values, while color channel values are not changed. When channel values are colors and mapping is enabled, only the luminance of channel color is taken into account.
Scattering
Checkbox – Enables scattering in this volume.
Channel – Selects the channel that is used as a source for scattering albedo. Along with channels (grids) presented in the FumeFX object, a special option can be selected:
Channel - Contains only the value 1, which fills the whole bounding box of the volume grid.
Tint – Enables modulation of the final color by a text map. Only object XYZ and World XYZ mapping are supported.
Scale– Uniformly scales scattering albedo after channel mapping.
Directionality– Directionality equal to 0 produces isotropic (diffuse) scattering, positive values produce forward scattering, and negative values produce backward scattering. The default value of 0 is suitable for most media, with the exception of clouds where a higher positive number produces the effect of a silver lining. Values close to - 1 or 1, increase the amount of image noise.
Single bounce only – When enabled, only a single bounce (direct lightninglighting) is scattered in the medium. This results in a biased (darker), but faster, rendering. Useful, for example, for rendering god rays.
Channel color mapping – Opens the Channel color mapping window, where you can choose how values from the selected channel are mapped to colors. Use the checkbox to enable mapping of channel value to colors. If mapping is switched off, float channel values are treated as luminance values, while color channel values are not changed. When channel values are colors and mapping is enabled, only the luminance of channel color is taken into account.
Rendering
Step size– Determines ray marching step size. Increasing the value leads to faster rendering with more noise and possibly some artifacts, while lowering the value leads to less noise but slower render times.
Enable Motion Blur– Toggles motion blur on and off.
Velocity multiplier– Specifies thestrength of the motion blur effect.
Alpha mode – Specifies how the object contributes to the alpha channel:
Default – Alpha depends on the transparency of the effect (e.g. smoke renders as white against a black background).
Always black – There is no alpha channel contribution.
Always white – The whole object appears as pure white in the alpha channel (including the bounding box of the FumeFX simulation).
