The emitter attributes in the Fluid Attributes section of the emitter Attribute Editor are described below.
For details on the standard emitter attributes, see Edit attributes of an emitter.
Select one of the following emitter types:
Emits fluid properties from randomly distributed positions on or near a NURBS or polygonal surface. When you emit from an object, the emitter is a surface emitter. For information, see Display fluid container contents.
Fluid emits on the set Start Frame and continues in all advanced frames for the duration of the simulation.
Fluid emits on the set Start Frame. Emission stops on the next advanced frame.
Scales the individual emitter rate for all the fluid grids in the container, including Density, Temperature, Fuel, and Speed. The Rate (Percent) value is set as a percent with 100 as the default value.
The final emission rate of fluid grids is determined by the emitter Rate (Percent) value and the contents emission method and rate. See Fluid Attributes.
When on, the emission rate of the fluid based is based on the per-particle rate value of the nParticle (or classic particle) that emits fluid. When off, the fluid emission rate is determined by the fluid emitter Rate (Percent) value. See Emit fluid properties with nParticles.
When on, you can control the emission radius of the fluid based on the per-particle Radius value of the nParticle (or classic particle) that emits fluid. When off, the fluid emission radius is determined by the fluid emitter's Max Distance value. See Emit fluid properties with nParticles and Max Distance.
Cycling emission restarts the random number stream after an interval in frames, specified by the Cycle Interval attribute.
Setting “Cycle Emission” to Frame and Cycle Interval to 1 causes the random stream to restart every frame. Cycle Interval values greater than 1 can be used to generate cycles for games work.
This only resets the random stream used by the emitter. It does not reset the random number stream used by MEL, shaders, and so on. Note also that the Frame option resets at most once per frame. However, oversampling does not affect the results.
When on, emission distance is set using the Min Distance and Max Distance values for surface and curve emitters. In previous versions of Maya, to use Min Distance and Max Distance with surface and curve emitters, Min Distance has to be set to a value other than 0. You can now set Min Distance to 0 for surface and curve emitters.
Use Distance is ignored by volume emitters, which do not use Min Distance and Max Distance, and by omni emitters, which always use Min Distance and Max Distance.
When on, fluid properties emit into the volume of selected geometry. To use Fill Object, the Emitter Type must be set to Surface.
Selects the 2D texture you want to map to density emission. Using a Density Emission Map, you can map a 2D texture to control emitted density.
When a surface emitter is used, emission is mapped to the surface object’s UV texture coordinates. When a volume emitter is used, the fluid’s emission is mapped to a UV projection that matches the volume’s shape. For example, Cube volumes are mapped with planar projections, while Sphere volumes are mapped with spherical projections. Density emission values are multiplied by the texture values. See also Emit fluids using emission maps.
Selects the 2D texture you want to map to heat emission. Using a Heat Emission Map, you can map a 2D texture to control emitted heat, which includes temperature.
When a surface emitter is used, emission is mapped to the surface object’s UV texture coordinates. When a volume emitter is used, the fluid’s emission is mapped to a UV projection that matches the volume’s shape. For example, Cube volumes are mapped with planar projections, while Sphere volumes are mapped with spherical projections. Temperature emission values are multiplied by the texture values. See also Emit fluids using emission maps.
Selects the 2D texture you want to map to fuel emission. Using a Fuel Emission Map, you can map a 2D texture to control emitted fuel.
When a surface emitter is used, emission is mapped to the surface object’s UV texture coordinates. When a volume emitter is used, the fluid’s emission is mapped to a UV projection that matches the volume’s shape. For example, Cube volumes are mapped with planar projections, while Sphere volumes are mapped with spherical projections. Fuel emission values are multiplied by the texture values. See also Emit fluids using emission maps.
Sets the dropoff value for fluid emission. For Volume emitters the dropoff specifies how much the emission drops off as you move away from the volume axis (dependent on the volume shape). For Omni, Surface, and Curve emitters the drop off is based on the emission point and radiates out from Min Distance to Max Distance.
Click the color swatch and select the emitted fluid color from the Color Chooser. This color is used only when Emit Fluid Color is turned on.
The default color of a fluid grid is grey and when this color is emitted it blends into other instances of grey, which can create grey fringes. To resolve this, set the initial state of the fluid color grid to a preferred color. You can also use two emitters: one for density emission and a larger one with no dropoff that only emits color.
The relative intensity of a second higher frequency turbulence. This can be used to create fine features in large scale flows. Both the speed and the frequency on this second turbulence are higher than the primary turbulence. When the Detail Turbulence is non-zero the simulation may run a bit slower, due to the computation of a second turbulence.
Since Maya Fluid Effects are solved as incompressible fluids, emitting speed into a fluid container can not have the same effect as emitting speed with particles. For fluids, any speed emitted into a fluid that creates motion away from or towards a point would fight the incompressibility of the fluid. Therefore, this type of behavior is not supported by fluid emission speed.
Determines how velocity emission values are set in the fluid.
Adds emitted velocity into the fluid as a rate each simulated step for the duration of the simulation. The amount of velocity emitted into the fluid is determined by the emitter Rate (Percent) value. See Rate (Percent).
Sets the amount of velocity that is inherited by the fluid from the translation velocity generated by an animated emitter. Inherited Velocity is added to the Rate (Percent) value to generate an overall emission velocity.
Inherit Velocity is calculated only when an animated emitter is present, which generates the translational velocity, or when nParticle velocity is present, such as when an nParticle object is emitting fluid.
Sets the emission speed along the normals of a surface when a fluid is emitted from a surface. Normal Speed applies only when the Emitter Type is set to Surface. See Emitter Type.
Sets the emission speed along the tangents of a curve when a fluid is emitted from a curve. Tangent Speed applies only when the Emitter Type is set to Curve. See Emitter Type.
Sets the emission speed along the central axis of all volume emitters. The central axis is defined as positive-Y for cube and sphere volumes. Along Axis applies only when the Emitter Type is set to Volume. See Emitter Type.
Sets the speed around the central axis of all volume emitters. Around Axis applies only when the Emitter Type is set to Volume. See Emitter Type.
When on, dropoff for volume emitters is fixed relative to the emitter’s scale, rather than to Worldspace. This ensures that fluid simulations remain consistent if the fluid container and emitter are scaled together. It also improves Fluid Dropoff for Cube volume emitters by using a smooth dropoff towards the volume boundaries. In previous versions of Maya, a cylindrical pattern dropoff is used with Cube volume emitters.
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