Extra V-Ray fluid attributes
Fluid shading quality
Additional V-Ray attributes can be added to fluid shape nodes in Maya. If these attributes are not present, the default volume shader will be used and the shading quality will be determined automatically taking into an account the "Quality" fluid attribute and the cell size. Note that there isn't exact correlation with the shading quality of the Maya Software renderer.
Volume Shader - determines which volume shader to use. Currently two shaders are available - VRayEnvironmentFog and Phoenix FD. By default, V-Ray will use the Phoenix FD shader if available.
Scatter GI - enables the tracing of GI through the fluid - the engine(s) currently specified in the GI option will be used to accelerate the tracing.
Scatter bounces - when Scatter GI is enabled, this controls the number of GI bounces that will be calculated inside the fog.
Simplify textures for GI - when this option is checked V-Ray will use a simplified method for calculating the GI when rendering parts of the liquid that are textured or are being faded out.
Step size - determines the size of one step through the volume of the liquid. Smaller steps produce more accurate results but are slower to render. In general, dense volumes require smaller step sizes than more transparent volumes.
Max steps - specifies the maximum number of steps through the liquid
Texture samples - determines the number of texture samples for each step through the liquid. This allows to sample textures more accurately than the volumetric lighting. It is useful in cases where the textures vary much faster than the lighting itself (e.g. for detailed fractal textures).
Cut-off threshold - this parameter controls when the raymarcher will stop traversing the volume. If the accumulated volume transparency falls below this threshold, the volume will be considered opaque and tracing will be aborted. Higher values make the rendering faster but may introduce artifacts.
Subdivs - determines the number of points inside the fog at which volumetric lighting is evaluated. If this value is 1, a single sample along the ray will be calculated, otherwise the Step size will be used instead.
Diffuse color multiplier - specifies an extra multiplier for the diffuse lighting. This can be used to produce non-physical result, closer to the one produced by the Maya Software renderer.
Jitter - this parameter can be used to offset the starting point of shading in order to hide regular patterns.
Solid mode - if enabled, the fluid will be rendered as a solid object with sharp surface, determined by the Solid threshold attribute.
Solid threshold - specifies the value bellow which the fluid is assumed to be "solid".
Use light cache - (Phoenix FD) turn on using of light cache. This can increase the performance, but can present lighting splotches, especially when used with noise textures.
Full Motion Blur - (Phoenix FD) turn on the motion blur caused by the fluid movement inside the container. This is slower then calculating only the motion blur of the fluid container.
- The ambient and fake lighting in the "Lighting" rollout are not currently supported.
- The "Self Shadowing" option is ignored, and the shadow option of the lights is taken into an account.
- The VRayEnvironmentFog shader do not support accurate blending of intersecting fluids.