fluidShape node

Manage a fluid shape

This node is MP safe

Node name	Parents	Classification	MFn type	Compatible function sets
fluidShape	surfaceShape	drawdb/geometry/dynamics/fluidShape:shader/volume/fog:shader/volume/particle	kFluid	kBase kNamedObject kDependencyNode kDagNode kShape kGeometric kSurface kFluid

Related nodes

diskCache, geoConnector, cacheFile

Attributes (426)

Attribute quick index omitted (too many attributes to show them all).

Long name (short name) Type Default Flags

outGrid (out) fluid NULL

The output grid.

currentTime (cti) time 0.0film

This is the current time used for the fluid simulation. By default, it is given an incoming connection from the main time node. This can be replaced with some other connection (e.g. from an expression or param curve), and then the solving is done based on that time value. There must be some incoming connection in order for the fluid object to simulate.

startTime (sti) time 0.0film

The time after which the simulation will be run for this fluid object. This is set from the startFrame attribute. Users should set startFrame instead of this attribute.

startFrame (stf) double 1.0

This is the frame after which the simulation will run. Nothing will play back for this object prior to startFrame.

lastEvalTime (lst) time -1.0film

This gets the value from currTime "copied" into it at the end of the solving process. This attribute affects no others so that requesting this attribute does not trigger any other evaluation. Because of the timing of when this attribute gets set, it should not be used by users as reliable data. It is for internal computation only.

disableInteractiveEval (die) bool false

Used to turn off memory allocation, solving and contents draw during interactive, but still allows batch render

is2d (is2) bool false

Used to specify whether this is a 2D or 3D fluid.

baseResolution (bres) integer 10

This defines the major axis resolution of the grid when square voxels or auto resize is enabled. With auto resize this additionally defines the resolution at the start frame, after which the resolution may change.

squareVoxels (sqvx) bool false

Square Voxels sets the fluid resolution in xyz based on the the fluid base resolution and size attributes such that fluid voxels are kept square in the local space of the fluid. Square voxels are generally preferable for solving a fluid and will also result in better render sampling of the fluid. As well with square voxels enabled the resolution of a fluid may be more easily adjusted by simply increasing or decreasing the Base Resolution attribute. Note that with Square Voxels ON the fluid resolution will also change if the proportion of the fluid size attribute changes. The Base Resolution defines the resolution along the largest axis of the fluid. The resolution along the smaller dimensions will be reduced in order to keep the voxels square. Note that if one changes the size attribute of the fluid the resolution will not change as long as the proportionality(or shape) of the fluid does not change. Also if the fluid transform has a non-proportional scale that the voxels will no longer be square in world space( only local space of the fluid ). When the auto resize feature is used then square voxels is always ON.

resolution (res) compound n/a

Resolution of the grid Users should be aware that changing this attribute will affect the density currently contained in the grid.

resolutionW (rw) integer 10

Resolution of the grid - width

resolutionH (rh) integer 10

Resolution of the grid - height

resolutionD (rd) integer 10

Resolution of the grid - depth

dimensions (dim) compound n/a

Dimensions of the grid. The dimensions are used internally by the solver and should not be changed unless you really know what you're doing. Use the scale on the transform to increase the size of the grid instead.

dimensionsW (dw) double 3

Width Dimension of the grid

dimensionsH (dh) double 3

Height Dimension of the grid

dimensionsD (dd) double 3

Depth Dimension of the grid

autoResize (aure) bool false

If auto resize is enabled then the fluid will dynamically change resolution and position based on whether or not there is density at the fluid boundaries. The start resolution of the fluid will be determined by the base resolution attribute, and square voxels is always ON when auto resize is used.

resizeClosedBoundaries (rcbd) bool true

If this is enabled then auto resize will affect both open and closed boundaries. The state of a boundary is determined by the BoundaryX,Y,Z attributes and the default is for all boundaries to be closed, in which case this toggle must be on for auto resize to affect the simulation. Note that Auto resize never affects wrapping boundaries.

autoResizeThreshold (aurt) float 0.01

This is the density required to expand a boundary when auto resize is on. If the density at a boundary is lower than this value then the fluid will shrink at that boundary, otherwise it will grow.

maxResolution (mres) integer 200

This defines the maximum total resolution of the fluid that the auto resize feature can achieve. This limits the total voxels to the cube of this value or maxResolution*maxResolution*maxResolution, however the fluid may be longer than this value on a side as long as the total number of voxels does exceed this limit.

resizeToEmitter (rste) bool true

If this is enabled then auto resize will expand to fit emitters. This allows the fluid to better track fast moving emitters. As well it allows the fluid to jump to the emitter location at the start frame when the emitter lies outside the fluid.

resizeInSubsteps (riss) bool true

Compute auto resize within substeps, instead of once per step. This is especially useful when the fluid is moving very quickly.

autoResizeMargin (armg) integer 0

This defines how many extra layers of empty voxels to maintain around auto resizing boundaries. Larger values will allow the flow to propagate more naturally and better hide the effect of the boundaries. For fast moving flows fewer substeps may be required.

dynamicOffset (dofs) compound n/a

This is a local space translation of the fluid that is computed by the auto resize feature. It is set by the auto resize computation or by the read of a cache file.

dynamicOffsetX (dofx) double 0

Translation of the grid in the localspace X direction.

dynamicOffsetY (dofy) double 0

Translation of the grid in the localspace Y direction.

dynamicOffsetZ (dofz) double 0

Translation of the grid in the localspace Z direction.

initialConditions (inc) Message n/a

Initial conditions for the fluidShape - currently unused.

doFields (dfr) bool true

A toggle - if false, ignore all connected fields

inputForce (ifc) vectorArray empty

This is the input multi-attribute where any fields acting on this fluid object are connected. The input forces are collected when the outGrid does it's update.

fieldData (fd) compound n/a

This is the compound that holds all of the default attribute for the fields to connect to.

fieldDataPosition (fdp) vectorArray empty

This is the default place that the fields will get this fluidShape's position data from. These positions are the (worldspace) midpoints of the each cell.

fieldDataVelocity (fdv) vectorArray empty

This attribute stores the velocity for each cell, for the fields to use in calculations.

fieldDataMass (fdm) doubleArray empty

This is where connected fields get mass data for the fluid shape. The density of fluid for a particular cell is converted to an appropriate amount of mass for fields which consider mass.

fieldDataDeltaTime (fdt) time 0film

This is where the fields will get this fluidShape's timeStep size from.

fieldList (fll) compound n/a

Parent multi-attribute to store the field's function attribute connections. (No longer used)

fieldFunction (frf) compound n/a

Function attribute for field computation. No longer used - see the fieldData attributes and the inputForce for how a field is connected to a fluidShape

fieldFunction_Hidden (frfh) function NULL

For Internal Use Only
Function being applied at this attribute with the mappings cached for efficiency

fieldFunction_Raw (frfr) function NULL

For Internal Use Only
Actual function being applied at this attribute

fieldFunction_Inmap (frfi) compound n/a

For Internal Use Only
Mapping of node's function input parameters to function data input parameters

fieldFunction_InmapTo (frfit) short 0

For Internal Use Only
Node's internal function input parameter index

fieldFunction_InmapFrom (frfif) short 0

For Internal Use Only
Function data input parameter index

fieldFunction_Outmap (frfo) compound n/a

For Internal Use Only
Mapping of node's function output parameters to function data output parameters

fieldFunction_OutmapTo (frfot) short 0

For Internal Use Only
Node's internal function output parameter index

fieldFunction_OutmapFrom (frfof) short 0

For Internal Use Only
Function data output parameter index

doEmission (de) bool true

A toggle - if false, ignore all connected emitters

isFull (ifl) bool false

Tells any object whether this fluid object has room for more emission

inheritFactor (inh) double 0.0

Fraction of emitter velocity that density emitted into this object inherit.

seed (sd) integer 1

Random number stream seed for emitter's random number stream. Separate seed for each emitter. Set seeds equal to get identical stream. Resetting the seed at a particular frame will restart the stream.

fluidColorEmission (fce) bool false

Indicates whether color is being emitted along with density.

fluidReactantEmission (frm) bool false

Indicates whether the reaction grid is being emitted into along with density.

emissionList (eml) compound n/a

Parent attribute for emission function.

emissionFunction (emf) compound n/a

The function attribute an emitter gets connected to to emit into this fluidShape.

emissionFunction_Hidden (emfh) function NULL

For Internal Use Only
Function being applied at this attribute with the mappings cached for efficiency

emissionFunction_Raw (emfr) function NULL

For Internal Use Only
Actual function being applied at this attribute

emissionFunction_Inmap (emfi) compound n/a

For Internal Use Only
Mapping of node's function input parameters to function data input parameters

emissionFunction_InmapTo (emfit) short 0

For Internal Use Only
Node's internal function input parameter index

emissionFunction_InmapFrom (emfif) short 0

For Internal Use Only
Function data input parameter index

emissionFunction_Outmap (emfo) compound n/a

For Internal Use Only
Mapping of node's function output parameters to function data output parameters

emissionFunction_OutmapTo (emfot) short 0

For Internal Use Only
Node's internal function output parameter index

emissionFunction_OutmapFrom (emfof) short 0

For Internal Use Only
Function data output parameter index

slices (sli) integer 2

The number of slices to draw for each grid cell most aligned with the view direction when in 'slice' shaded draw mode. Increasing this value will give more detailed hardware draws (at the cost of slower drawing)

voxelQuality (vqu) enum 0

In hardware draw mode, we normally draw quads with vertices at the centers of voxels. If the VoxelQuality attr is set to 2 (Better), then we split this up, doubling the number of quads in each direction, for a total of 4.

drawSubVolume (dsv) bool false

When turned on, only a portion of the fluid's internal volume is is drawn, as specified by the next set of attributes.

subVolumeCenter (svc) compound n/a

The center (in voxel grid coordinates) of the sub-volume to be drawn.

subVolumeCenterW (scw) integer -1

Width component of aSubVolumeCenter.

subVolumeCenterW (scw) integer -1

Width component of aSubVolumeCenter.

subVolumeCenterH (sch) integer -1

Height component of aSubVolumeCenter.

subVolumeCenterH (sch) integer -1

Height component of aSubVolumeCenter.

subVolumeCenterD (scd) integer -1

Depth component of aSubVolumeCenter.

subVolumeCenterD (scd) integer -1

Depth component of aSubVolumeCenter.

subVolumeSize (svs) compound n/a

The dimensions (in voxels) of the sub-volume to be drawn.

subVolumeSizeW (ssw) integer -1

Width component of aSubVolumeSize.

subVolumeSizeW (ssw) integer -1

Width component of aSubVolumeSize.

subVolumeSizeH (ssh) integer -1

Height component of aSubVolumeSize.

subVolumeSizeH (ssh) integer -1

Height component of aSubVolumeSize.

subVolumeSizeD (ssd) integer -1

Depth component of aSubVolumeSize.

subVolumeSizeD (ssd) integer -1

Depth component of aSubVolumeSize.

lockDrawAxis (lda) bool 0

Determines whether the fluid drawing axis changes orientation with respect to the camera angle. If false, orientation of the draw slice is locked and does not change with the camera angle. If true, orientation changes as the camera angle changes.

boundaryDraw (bod) enum 0

This attribute controls how the grid is drawn in 3d views. 0 or "Bottom", the default, indicates the bottom 'wall' of the grid should be drawn, bounding lines only for the rest. 1, "Reduced" indicates draw the 'walls' for the three sides furthest away from the camera, lines for the rest. 2, or "Outline", draws all sides of the grid with full resolution. 3, or "Full", draws everything. "Bounding box", value 4, draws just the bounding box for the grid, and 5, or "None", means don't draw the grid at all.

drawHeads (dhd) bool true

If false, the velocity arrows are drawn as line segments only. Will speed up drawing and may make the volume less cluttered for visualization.

velocityDraw (vld) bool false

If true, draws arrows or lines for the veloicty field.

velocityDrawLength (vdl) double 1

The larger this value, the longer the velocity segments or arrows. For very low-force simulations, the velocity field may be very small in magnitude. If this is the case, bumping this atribute up will help to visualize the velocity flow.

velocityDrawSkip (vds) integer 1

The larger this value, the less velocity arrows that are drawn If the value is 1 then every other arrow will be omitted. If it is zero then all arrows will be drawn.

shadedDisplay (sdp) enum 1

Shaded Display determines what is displayed in the modeling view when in shaded mode. As Render attempts to match the final software rendered look. The other methods allow one to view isolated sub elements of the fluid, which can be useful when painting or tweaking these elements. Tweak the Display Opacity Scale to map the current element to a useful range of opacity in the grid. The methods combining density with another attribute display this other attribute using color.

opacityPreviewGain (opg) float 0.5

Opacity Preview Gain adjusts the opacity of the hardware redraw when the shaded display is not As Render. This is useful when painting values into the grid.

wireframeDisplay (wdp) enum 2

How to simulate the opacity of the grid when in wireframe mode.

numericDisplay (nud) enum 0

Display selected attribute as a grid of numbers.

hardwareSelfShadow (hss) bool true

A toggle to turn self-shadowing on or off during the hardware draw. Currently this attribute is only used in 'slice' draw mode. A directional light <-1,-1,-1> is the only light used to compute self-shadowing currently.

coordinateMethod (cmet) enum 0

This defines how texture coordinates are defined. Fixed sets the values to equal the object space coordinate system (0-1 for the volume in x,y and z). Grid uses a grid of points and interpolates for in between values. If grid is set then the coordinate values will be moved using the current density solver. This will allow the texture to move and swirl with the density, rather than appearing fixed in space. File loads the texture coordinates from a file.

overrideTimeStep (ots) time 1.0film

Tells the emitter the time step to emit for: this is the time since the last evaluation times the simulation rate scale.

simulationRateScale (srs) float 1

Scale the time step used in emission and solving

gridInterpolator (gdi) enum 0

Which interpolation algorithm to use when retrieving values from fractional points within a fluid grid. Linear is the fastest. Linear with collisions or Hermite must be used for friction at boundaries to be computed. Hermite causes less diffusion than linear, but will make the simulation run several times more slowly, especially when one has collisions with geometry.

forceDynamics (fdn) bool false

By requesting this attribute, the fluid will be forced to evaluate. used for runup.

solver (sol) enum 1

Which solver to use. "Navier-Strokes" is a fast Navier-Stokes solver. "Spring Mesh" defines a simple water surface.

solverQuality (sql) integer 20

Increasing the quality will increase the number of steps used internally by the Navier-Stokes solver to determine incompressibility, which may increase the accuracy of the simulation and will certainly increase the time required to run. Depending on your fluids material properties, you may get satisfactory results lowering this from the default value of 20.

substeps (sbst) integer 1

Increasing the substeps will increase the number of solver time steps used internally. This can be especially useful to help make the simulation stable when using the highDetailSolve method for fast moving fluids. When velocity is high relative to the voxel size the highdetail solve method can blow up. By taking smaller time steps the velocity per step is proportionally less.

emitInSubsteps (eiss) bool false

Compute emission within substeps, instead of once per step. Note that motion streak on the emitter will always compute a full frame streak of the emitter motion for each substep, rather than advancing within a substep. The emission location does not change between substeps. This parameter is primarily useful when one has very fast speed of flow coming off of an emitter, like an explosion, as opposed to the emitter being in motion.

highDetailSolve (hds) enum 0

This attribute can be used to create more detailed simulations without requiring higher resolution grids. With highDetailSolve turned off simulations will run faster, but there will be a lot of diffusion of both density and velocity as the the simulation progresses. The velocity grid is used not only to push around other grid values, like density, but it also pushes its own velocity values to new positions in the grid. Propagating velocity is much more computationally intensive than propagating scalar grid values like density, thus enabling Scalar and Velocity will increase the simulation compute time by a factor of 2, while enabling just the scalar grids only will not slow the solve by much. There will be much more detail in the flow, however, when using the scalar and velocity setting. In some cases the effect of high detail on a scalar grid such as density may not look smooth enough, in which case the velocity only method might be preferable.

enableLiquidSimulation (elsm) bool false

This attribute allows one to setup a pouring liquid simulation. The default fluid behaves similar to a box filled to the brim with water where adding density to the fluid is like pouring milk into water. When enableLiquidSimulation is ON the density of the fluid affects how the mass is transferred across the fluid and we have a notion of a threshold density (liquidMinDensity) below which the fluid is treated as air.

liquidMethod (lmth) enum 0

With the Liquid and Air method the regions of the fluid below the Liquid Min Density are treated as zero mass, which allows the dense regions to move around without being restrained by the less dense regions. The density based mass method allows one to have the mass for interaction vary with the density, so that regions with no density still solve incompressibly and apply a force on the dense regions. A large value for the massRange will simulate the dense regions being much heavier than the empty regions, as would be the case with air and water. Unlike the liquid and air model this can simulate bubbles being trapped in the water and the way trapped volumes of air affect the motion of the water. Lower values for mass range could be used to simulate two interacting fluids such as oil and water.

liquidMinDensity (lqmd) float 0.5

Liquid Min Density defines the density grid value below which the fluid simulation is treated as being air. This is also used by the liquidMistFall feature to define the densities that are considered mist: all non-zero densities that are below this value.

liquidMistFall (lmsf) float 0

Liquid Mist Fall works when liquid simulation is enabled. It propagates downward the densities that are lower than liquid min density value. Spray can fall in a way that does not respect the incompressibility of the fluid air flow, so this downward propagation is done separately from the normal density advection. This parameter controls the downward speed of flow of the mist.

massRange (msrn) float 200

Mass Range works with the Density Based Mass simulation method. It defines how heavy the dense regions are compared to regions with no density. If the density represents water then this could be thought of as how many times heavier the water is than the air.

forwardAdvection (foad) bool false

Compute propagation of non-velocity grids using a mass conserving forward propagation technique. It has somewhat less diffusion than the standard method and generally fewer artifacts than the high detail solve propagation( it will use this instead of high detail solve for the non-velocity grids even if highDetail is enabled for those grids ). One artifact of this method is that density may compress along boundaries.

boundaryX (bndx) enum 1

This controls the way the solver treats density at the boundaries. A closed boundary is like a wall. An open boundary allows outflows. A wrapping boundary causes flows that go off one side to enter in the opposite side. This can be useful if you wish to have a windy fog, yet do not want to continually replenish the density at the inflowing regions.

boundaryY (bndy) enum 1

boundaryZ (bndz) enum 1

massConversion (mcv) double 1

This attribute controls how density is converted to mass for field operations.

falloffMethod (fmt) enum 0

This defines how the optional grid of falloff values (used to soften the opacity of the fluid in user-defined ways) is defined. These values are only used if the Dropoff Shape is set to Grid. Off sets the grid to 0.0 across the volume, meaning that the fluid will become completely transparent everywhere. Static Grid Uses a grid without dynamic behavior to store the falloff values.

densityMethod (dmt) enum 2

This defines how density is defined. Off sets the value to 0.0 across the volume. Static Grid Uses a grid without dynamic behavior. Dynamic Grid Uses a grid with a dynamic solver. Gradient ramps the value based on DensityGradient.

densityGradient (dgr) enum 0

This defines how density can be ramped Constant sets the value to 1.0 across the volume. X Gradient ramps the value from zero to one along the X axis. Y Gradient ramps the value from zero to one along the Y axis. Z Gradient ramps the value from zero to one along the Z axis. Center Gradient ramps the value from one at the center to zero at the edges.

densityScale (dsc) float 0.5

Density Scale multiplies the value determined by the Density Method

densityDissipation (dds) double 0

How much the density dissipates.

densityDiffusion (ddf) double 0

Diffusion of the density

conserveMass (cm) bool true

For the density update step - conserve mass on update or not.

densityBuoyancy (dsb) float 1.0

Density Buoyancy simulates a difference in mass density between the regions with density and the regions without. If the value is positive the density represents a substance that is lighter than the surrounding medium, like bubbles in water, and will thus rise. Negative values will cause the density to fall.

densityGradientForce (dsgf) float 0.0

Density Gradient Force applies a force along the direction of the density gradient. Positive values for this attribute push in the direction of increasing density, which acts somewhat like self attraction or surface tension. Negative values will tend to repel density from its self. While this is similar to the self force attribute it is faster to compute and more local in the nature of its effect.

densityTension (dstn) float 0.0

Density Tension applies a sharpen filter to the density grid each timestep. This has an effect somewhat like surface tension in a liquid and will tend to push the density into rounded shapes, which makes it useful for puffy cloud effects. It also is useful in combination with the highDetail solve method as it will tend to remove linear grid artifacts that this method produces.

tensionForce (tnsf) float 0.0

Tension Force applies a surface tension force based on the local curvature of the density grid. With liquid solving this simulates the surface tension property of of liquids. While the attribute Density Tension acts by directly modifying density values Tension Force instead modifies velocity, and thus imparts momentum to the fluid.

densityNoise (dsns) float 0.0

Density Noise randomizes the density voxel values based on the local velocity divergence. It can help add in detail to smooth flows, although high values may may look too jittery.

densityPressure (dspr) float 0.0

Density Pressure is the rate at which the density grid affects the local pressure of the fluid. It can be useful for keeping liquid simulations from contracting, especially when using forward advection. Forward advection can concentrate density, particularily along boundaries and density pressure can be used to apply pressure outward in regions that are over the densityPressureThreshold, thus keeping them from contracting. This would keep a water tank simulation from collapsing or appearing to drain.

densityPressureThreshold (dspt) float 1.0

Density Pressure Threshold is density value over which the density pressure kicks in. When the density is below this threshold it will not apply the density pressure effect.

selfForce (slfc) enum 0

This controls a force applied between voxels in the fluid. The force attempts to attract and repel voxels towards an equilibrium value. The attraction may be thought of as a force like gravity attracting clouds of gas in space. When the gas density is over an equilibrium point repulsive forces( such as the temperature of the gas ) overwhelm the attraction and push the gas apart. While the fluid cannot directly handle compression and expansion, this can be allowed by lowering the fluid quality attribute, which controls the amount of incompressibility of the fluid. When combined with the forward prop method the density can concentrate under attraction and dissipate under repulsion. When used with temperature one can make hot regions explosively repel. Off disables the self force. Density Applys a self force is based on the density grid values Temperature Applys a self force is based on the temperature grid values

selfAttract (sfat) float 0.1

Self Attract attracts voxel pairs based on the relative density (or temperature) value. The attraction falls off linearly with distance for 2d fluid and by an inverse square of distance for 3d fluids. Self attract has no effect on voxels that are over the equilibrium value(density or temperature).

selfRepel (sfrp) float 0.1

Self Repel pushes apart voxel pairs based on the relative density (or temperature) value. Self repel has no effect on voxels that are under the equilibrium value(density or temperature).

equilibriumValue (eqvl) float 0.5

This determines the target level of density (or temperature) for the self force feature. When voxels are below this level then they will attract together, while when the density is greater they will repel.

selfForceDistance (sfds) integer 16

This is the maximum distance between voxels for the self force effect to be applied. Large values can greatly slow the calculation speed of the fluid because the number of voxels comparisons required may increase by the cube of this value. Due to the dropoff of attraction with distance it is frequently sufficient limit this comparison distance to values much less than the size of the cube. This value is in voxels, so a value of 1 will only attract neighbor voxels. If this value is larger than the resolution of the fluid then each voxels will be attracted or repelled for every other voxel in the fluid.

gravity (grv) float 9.8

Gravitational constant that simulates mass of the world the simulation is occuring on. Values of zero simulate being in outer space. Note that density and heat buoyancy will have no effect if gravity is zero.

velocityMethod (vmt) enum 2

This defines how velocity is defined. Off sets the value to (0.0,0.0,0.0) across the volume. Center Gradient ramps the value from (1.0,1.0,1.0) at the center to (0.0,0.0,0.0) at the edges. Both grid methods use a grid of points and interpolatefor in between values. These are the required methods if dynamic emitters are to be used. Also required if one wishes to paint values for this attribute. Static Grid Uses a grid without dynamic behavior. Dynamic Grid Uses a grid with a dynamic solver. Gradient ramps the value based on VelocityGradient.

velocityGradient (vgr) enum 0

This defines how velocity can be ramped Constant sets the value to 1.0 across the volume. X Gradient ramps the value from (0.0,0.0,0.0) to (1.0,1.0,1.0) along the X axis. Y Gradient ramps the value from (0.0,0.0,0.0) to (1.0,1.0,1.0) along the Y axis. Z Gradient ramps the value from (0.0,0.0,0.0) to (1.0,1.0,1.0) along the Z axis. -X Gradient ramps the value from (1.0,0.0,0.0) to (0.0,0.0,0.0) along the X axis. -Y Gradient ramps the value from (0.0,1.0,0.0) to (0.0,0.0,0.0) along the Y axis. -Z Gradient ramps the value from (0.0,0.0,1.0) to (0.0,0.0,0.0) along the Z axis. Center Gradient ramps the value from one at the center to zero at the edges.

velocityScale (vsc) float3 1.0, 1.0, 1.0

Velocity Scale multiplies the value determined by the Velocity Method

velocityScaleX (vsx) float 0.0

The x component of the velocityScale

velocityScaleY (vsy) float 0.0

The y component of the velocityScale

velocityScaleZ (vsz) float 0.0

The z component of the velocityScale

viscosity (viy) float 0

This parameter determines how thick and non-liquid the material is. At high values it is like tar, while at low values it is like water. When this is 1, the material reynolds number is 0, when it is 0, the reynolds number is 100000. At a value of 0.5 the reynolds is 1.

friction (fri) float 0

Internal Friction in velocity solving

velocitySwirl (vsw) float 0

Amount of swirliness effects in velocity solution

velocityNoise (vsns) float 0

Add a random noise each step to velocity grid. This can help stimulate turbulence.

velocityDamp (vdp) float 0

Amount velocity solution is damped towards zero each time step. At a value the flow is totally suppressed. Small amounts of damping can be useful when boundaries are open to keep strong winds from building up and leading to instability.

velocityAdvect (va) bool true

Turn on velocity solver.

velocityProject (vi) bool true

Turn on projection for velocity solver

turbulenceStrength (tst) float 0

Increasing this will increase the amount of force applied by the turbulence

turbulenceFrequency (tfr) float 0.2

Lowering this will make the turbulence vortices larger. This is a spacial scale factor on the turbulence function and has no effect if the turbulence strength is zero.

turbulenceSpeed (tbs) float .2

Rate at which turbulence pattern changes over time

turbulenceRes (trs) integer 10

Scale of turbulence pattern relative to the fluid

temperatureMethod (tmet) enum 0

This defines how temperature is defined. Off sets the value to 0.0 across the volume. Static Grid Uses a grid without dynamic behavior. Dynamic Grid Uses a grid with a dynamic solver. Gradient ramps the value based on TemperatureGradient.

temperatureGradient (tgr) enum 0

This defines how temperature can be ramped Constant sets the value to 1.0 across the volume. X Gradient ramps the value from zero to one along the X axis. Y Gradient ramps the value from zero to one along the Y axis. Z Gradient ramps the value from zero to one along the Z axis. -X Gradient ramps the value from one to zero along the X axis. -Y Gradient ramps the value from one to zero along the Y axis. -Z Gradient ramps the value from one to zero along the Z axis. Center Gradient ramps the value from one at the center to zero at the edges.

temperatureScale (tmsc) float 1.0

Temperature Scale multiplies the value determined by the Temperature Method

temperatureDissipation (tds) double 0.1

Rate at which the temperature dissipates

temperatureDiffusion (tdf) double 0.1

Rate at which the temperature diffuses between voxels

temperatureTurbulence (ttb) float 0.1

Multiplier on the turbulence applied to the temperature

temperatureNoise (tmns) float 0.0

Temperature Noise randomizes the density voxel values at a constant rate. It can help add in detail to to the texture grid, which can help with renders and also with simulation. It differs from temperature turbulence in that the temperature grid is randomized each step whereas turbulence randomizes the velocity based on the the temperature grid.

temperaturePressure (tmpr) float 0.0

Temperature Pressure is the rate at which the temperature grid affects the local pressure of the fluid. It can be useful for creating explosion effects. With temperature pressure an emitted bit of fluid will turbulently expand outwards. It helps to use forward advection with this attribute because the backward advection does not preserve the total density and temperature when expanding or contracting.

temperaturePressureThreshold (tmpt) float 0.0

Temperature Pressure Threshold is temperature value over which the temperature pressure kicks in. When the temperature is below this threshold it will not apply the temperature pressure effect.

buoyancy (buo) float 3

Built in buoyancy strength for temperature solving

temperatureTension (tttn) float 0.0

Temperature Tension applies a sharpen filter to the temperature grid each timestep. This has an effect somewhat like surface tension in a liquid and will tend to push the temperature into rounded shapes. It can also make the temperature boundary more defined.

colorMethod (cmt) enum 0

This defines how color is defined Off use the Shading Color instead Static Grid Uses a grid without dynamic behavior. Dynamic Grid Uses a grid with a dynamic solver.

colorDissipation (cds) double 0

How much the color dissipates.

colorDiffusion (cdf) double 0

Diffusion of the color

fuelMethod (fmet) enum 0

This defines how the fuel value is defined. Off sets the value to 0.0 across the volume. Dynamic Grid Creates a grid for the fuel. This grid will be transported along with the density grid. The grid method must be used for the fuel to evolve over time. Gradient ramps the value based on FuelGradient.

fuelGradient (fgr) enum 0

This defines how fuel can be ramped Constant sets the value to 1.0 across the volume. X Gradient ramps the value from zero to one along the X axis. Y Gradient ramps the value from zero to one along the Y axis. Z Gradient ramps the value from zero to one along the Z axis. -X Gradient ramps the value from one to zero along the X axis. -Y Gradient ramps the value from one to zero along the Y axis. -Z Gradient ramps the value from one to zero along the Z axis. Center Gradient ramps the value from one at the center to zero at the edges.

fuelScale (fesc) float 1.0

Fuel Scale multiplies the value determined by the Fuel Method

reactionSpeed (resp) float 0.05

Reaction Speed determines how quickly the reaction converts from a value of 1 to zero when the temperature is at or above the Max Reaction Temperature value. A value of 1.0 will result in an instantanious reaction.

fuelIgnitionTemp (fuit) float 0.0

Fuel Ignition Temp determines the lowest temperature at which a reaction will occur. The reaction rate is zero at this temperature increasing to the value defined by the Reaction Speed at the Max Reaction Temperature.

maxReactionTemp (mxrt) float 1.0

Max Reaction Temp determines the temperature beyond which which a reaction occurs at the fastest speed.

airFuelRatio (afrt) float 0.0

The Air Fuel Ratio defines the mix of air to fuel at which there is just enough air to react all the fuel. This is know as the Stoichiometric ratio. For gasoline the value of this is about 15, or 15 times as much air as fuel. This parameter will result in the fuel only burning where it mixes(diffuses) into the air. This results in a more natural looking boundary and shape to a flame. If this is set to zero then the fuel will instead burn uniformly, as if it contained its own oxygen.

heatReleased (hre) float 1.0

Heat Released determines how much much heat is released into the temperature grid by a total reaction. This is how many reactions sustain themselves after an initial spark of ignition. The amount of heat added in a given step is proportional to the percentage of reacted material. One needs to have the Temperature Method set to Grid to use this option.

lightReleased (lre) float 0.0

Light Released determines how much much light is released by the reaction. This is directly added into the final incandescent intensity of the shading and does not input into any grids.

lightColor (lco) float3

Light Color is the color of the light released by the reaction. The parameter Light Released along with the amount of fuel reacted in a given time step scales the overall brightness of this light.

lightColorR (lcor) float 1.0

light color red value

lightColorG (lcog) float 1.0

light color green value

lightColorB (lcob) float 1.0

light color blue value

usePre70Dynamics (updy) bool false

Match the pre Maya7.0 dynamics behavior for the fluid. In 7.0 the damp, reactionSpeed and turbulence intensity were modified to preserve behavior when changing the frame rate or the sample rate. If you have loaded a fluid an older file this variable will automatically be enabled. If you wish the new behavior for such scenes use setAttr to turn off this attribute.

outMesh (o) mesh NULL

Output implicit surface.

inputData (ind) compound n/a

Data from dynamic nodes for computing new output force. The field gets data from a set of "points" (particles, locations on a rigid body, etc.) and returns a force computed for each point. Arbitrary user-defined nodes can make use of the field as Tint32 as they can give data for a set of points and can interpret the outputs. Nodes using the field should take care to set up their attributes so as not to cause a DG loop.

inputPositions (inp) vectorArray empty

Input position array

inputVelocities (inv) vectorArray empty

Input velocity array

inputMass (inm) doubleArray empty

Input mass array

deltaTime (dt) time 0film

Some fields may need deltaTime to compute force. Of the standard nodes, vortex is the only one. User-defined nodes can use this attribute if they wish.

inputForce2 (in2) vectorArray empty

Force data from dynamic nodes for computing new output force. If an array of forces is supplied here, the field will ADD its force to that array instead of writing it to outputForce. The particle shape uses this to gain some important efficiencies.

outputForce (of) vectorArray empty

Force data output to dynamic nodes. The entries in this output array match the input entries in inputPositions et al.

matteOpacityMode (mom) enum 2

Matte Opacity Mode controls how the system will use the Matte Opacity attribute (below). When you are rendering with a matte (i.e. an alpha channel, or mask), these two attributes are used to control how this material will show up in the matte. This is useful if you will be compositing your rendered images later on.

There are three settings, used for different purposes:

Opacity Gain

Solid Matte: This is like Opacity Gain, except that the normally-calculated matte values are ignored in favor of the Matte Opacity setting. The entire matte for the object is set to the value of the Matte Opacity attribute. If there are transparent areas on the object, their transparency is ignored in the matte. Use this setting to composite an object with transparent parts, when you don't want the background to show through them.

Black Hole: The value of Matte Opacity is ignored, and all the matte for this material is set to be transparent. Use this when you are creating substitute geometry in a scene, which is standing in for objects in a background image that you will be compositing with later. Your stand-in objects will 'punch a hole' in the matte. This allows other computer-generated geometry to pass behind your stand-in objects. Later, when foreground and background are composited, the results will be correct, with the background object showing through the 'black hole' areas.

matteOpacity (mog) float 1.0

Matte Opacity is used (along with Matte Opactiy Mode) to affect how the matte (i.e. alpha channel or mask) for this material will be calculated. See Matte Opacity Mode above for full details.

filterSize (fs) float3 0.0, 0.0, 0.0

The current sample size that has to be shaded

filterSizeX (fsx) float 0.0

The x component of the current sample position

filterSizeY (fsy) float 0.0

The y component of the current sample position

filterSizeZ (fsz) float 0.0

The z component of the current sample position

matrixEyeToWorld (e2w) fltMatrix identity

The transform to go from eye to world space

matrixWorldToObject (w2o) fltMatrix identity

The transform to go from world to object space

pointWorld (pw) float3 0.0, 0.0, 0.0

The current start point of the volume interval

pointWorldX (pwx) float 0.0

The x component of the current sample position

pointWorldY (pwy) float 0.0

The y component of the current sample position

pointWorldZ (pwz) float 0.0

The z component of the current sample position

farPointWorld (fw) float3 1.0, 1.0, 1.0

The end of the volume interval in world space.

farPointWorldX (fwx) float 0.0

The x-component of the world far-position.

farPointWorldY (fwy) float 0.0

The y-component of the world far-position.

farPointWorldZ (fwz) float 0.0

The z-component of the world far-position.

pointObj (po) float3 0.0, 0.0, 0.0

The current start point of the volume interval in object space

pointObjX (pox) float 0.0

The x component of the current sample position

pointObjY (poy) float 0.0

The y component of the current sample position

pointObjZ (poz) float 0.0

The z component of the current sample position

farPointObj (fo) float3 1.0, 1.0, 1.0

The end of the volume interval in world space.

farPointObjectX (fox) float 0.0

The x-component of the object space far-position.

farPointObjectY (foy) float 0.0

The y-component of the object space far-position.

farPointObjectZ (foz) float 0.0

The z-component of the object space far-position.

rayInstance (ryi) integer 0

Unique ray identifier controlling the sampling distribution for volume light depth map shadows, fluid volume rendering, light fog, ray traced shadows, and motion blur.

lightDataArray (ltd) lightData NULL

The lighting information this node computes.

lightDirection (ld) float3

The light direction.

lightDirectionX (ldx) float 1.0

The x component of the direction.

lightDirectionY (ldy) float 1.0

The y component of the direction.

lightDirectionZ (ldz) float 1.0

The z component of the direction.

lightIntensity (li) float3

The light intensity (it's a colour).

lightIntensityR (lir) float 1.0

light intensity red value

lightIntensityG (lig) float 1.0

light intensity green value

lightIntensityB (lib) float 1.0

light intensity blue value

lightAmbient (la) bool true

The boolean that indicates if the light has an ambient component.

lightDiffuse (ldf) bool true

The boolean that indicates if the light has a diffuse component.

lightSpecular (ls) bool false

The boolean that indicates if the light has a specular component.

lightShadowFraction (lsf) float 0.0

The visibility fraction to the light. value is in [0,1]

preShadowIntensity (psi) float 0.0

The light intensity without taking shadow into account.

lightBlindData (lbd) addr 0

The light's blind data.

selfShadowing (ss) bool false

Determines whether self-shadowing should be computed or not

quality (qua) float 1.0

Quality determines the quality (number of samples per ray) used in the rendering

renderInterpolator (rin) enum 0

Which interpolation algorithm to use when retrieving values from fractional points within a fluid grid when shading a ray. Sharply contrasting densitys may show grid artifacts( like a mesh with no normal smoothing ) with linear interpolation. Smooth interpolation renders slower, but gets rid of these problems.

color (cl) compound n/a

Color defines a range of color values used to render the volume. The particular color selected from this range is determined by the Color Input parameter. The color represents how much incoming light is absorbed or scattered. If it is black all light is absorbed, while white materials scatter all incoming light.

color_Position (clp) float 0.0

Position of ramp value on normalized 0-1 scale

color_Color (clc) float3

Ramp color at the sibling position

color_ColorR (clcr) float 0.0

Ramp red channel value at the sibling position

color_ColorG (clcg) float 0.0

Ramp green channel value at the sibling position

color_ColorB (clcb) float 0.0

Ramp blue channel value at the sibling position

color_Interp (cli) enum 0

Ramp Interpolation controls the way the intermediate values are calculated. The values are:

None

Linear: The values are interpolated linearly in RGB color space.

Smooth: The values are interpolated along a bell curve, so that each color on the ramp dominates the region around it, then blends quickly to the next color.

Spline: The values are interpolated with a spline curve, taking neighboring indices into account for greater smoothness.

colorInput (coi) enum 0

Defines a the attribute used to index the color value. Constant sets the input to 1.0 or the end of the ramp. Color overrides the color range using the value defined by the grid and the color scale. This is useful when using color emission into the grid. The other options all sets the input to corresponding value from the grid. For example if density is used the start of the color ramp will be used for density values of 0 and the end value for densities of 1.0. The way midrange values map out is determined by the Color Input Bias

colorInputBias (cib) float 0.0

Color Input Bias adjusts the sensitivity of the selected color input used. Input values of 0 and 1 will always map to the start and end of the ramp value, although the bias determines where in the ramp a value of 0.5 will index. For example if one used density as an input, and the material becomes relatively opaque at a density of 0.001, then the density bias can be used to shift most of the ramp into this density range. This is easier Instead of cramming several values at the beginning of the ramp one can use the full range. If the input bias is 0.0 then a value of 0.5 will map to the exact middle of the color ramp.

opacity (opa) compound n/a

Opacity defines a range of opacity values used to render the volume. The particular opacity value selected from this range is determined by the Opacity Input parameter. The opacity represents how much the material will block light. If the opacity is zero then the material is totally transparent.

opacity_Position (opap) float 0.0

Position of ramp value on normalized 0-1 scale

opacity_FloatValue (opafv) float 0.0

Ramp value at the sibling position

opacity_Interp (opai) enum 0

Ramp Interpolation controls the way the intermediate values are calculated. The values are:

None

Linear: The values are interpolated linearly in RGB color space.

Smooth: The values are interpolated along a bell curve, so that each color on the ramp dominates the region around it, then blends quickly to the next color.

Spline: The values are interpolated with a spline curve, taking neighboring indices into account for greater smoothness.

opacityInput (opi) enum 5

Defines a the attribute used to index the opacity value. Constant sets the input to 1.0 or the end of the curve. The other options all sets the input to corresponding value from the grid. For example if density is used the start of the curve will be used for density values of 0 and the end value for densities of 1.0. The way midrange values map out is determined by the Opacity Input Bias

opacityInputBias (oib) float 0.0

Opacity Input Bias adjusts the sensitivity of the selected opacity input used. Input values of 0 and 1 will always map to the start and end of the opacity curve, although the bias determines where in the curve a value of 0.5 will index. For example if one used density as an input, and one wishes the material to become opaque at a density of 0.001, then the density bias can be used to shift most of the curve into this density range. Instead of cramming several values at the beginning of the ramp one can use the full range. If the input bias is 0.0 then a value of 0.5 will map to the exact middle of the opacity curve.

transparency (t) float3

Transparency combined with Opacity determine how much light can penetrate the defined density. Transparency scales the single channel opacity value allowing for a colored opacity. Note that a transparency of 0.5 0.5 0.5 may render slightly faster than other values.

transparencyR (tr) float 0.25

transparency red value

transparencyG (tg) float 0.25

transparency green value

transparencyB (tb) float 0.25

transparency blue value

shadowOpacity (shp) float 0.5

ShadowOpacity used to brighten-up or darken shadows cast from the volume. At 0.5 the shadows are attenuated in exact proportion to the transparency of the volume. At 0.0 no shadowing occurs and at 1.0 shadows are completely black and the volume is totally in shadow. To account for multiple-scattering values less than 0.5 can help make thick clouds appear more translucent. Values above 0.5 make the clouds unnaturally opaque to lights, but may be useful to accentuate self shadowing.

shadowDiffusion (sdfu) float 0.0

ShadowDiffusion will blur the internal shadows simulating local light scattering. Currently this only affects hardware draw of the fluid in the viewports.

lightType (ltyp) enum 1

Defines the type of the internal light used for both faster batch rendering as well as hardware shaded display of the fluid in the viewports. Diagonal is a fixed directional light down the diagonal of the fluid in the xy plane. In older releases of Maya the hardware shading was restricted to this direction, which is simpler to implement than an arbitrary direction. Directional simulates a light source that is far away shining along the direction vector. Point simulates a point light source where the pointLight position is defined in local space of the fluid node.

lightBrightness (lbrt) float 1.0

LightBrightness This is the brightness of the internal light used when either Real Lights is enabled or for the hardware shaded display of the fluid.

pointLightDecay (pldy) enum 1

The decay determines how fast the internal point light diminishes with distance. Quadradic simulates the decay from a perfect point light source. However a faster decay could simulate being in a more absorbtive medium, and mimic self shadowing of the fluid if self shadowing was turned off.

fluidLightColor (flic) float3

FluidLightColor is the color for the internal light.

fluidLightColorR (flir) float 1.0

fluidLightColor red value

fluidLightColorG (flig) float 1.0

fluidLightColor green value

fluidLightColorB (flib) float 1.0

fluidLightColor blue value

ambientBrightness (abrt) float 0

AmbientBrightness This is an internal ambient light that does a simple ambient occlusion prepass computation within the fluid grid.

ambientDiffusion (adfu) float 2.0

AmbientDiffusion This determines how the ambient light diffuses into the density. Initially the ambient light intensity is the inverse of the opacity. This blurs the resulting factor to provide a fast ambient occlusion term.

ambientColor (ambc) float3

AmbientColor is the color for the internal ambient light.

ambientColorR (ambr) float 0.5

ambientColor red value

ambientColorG (ambg) float 0.7

ambientColor green value

ambientColorB (ambb) float 1.0

ambientColor blue value

incandescence (i) compound n/a

Incandescence controls the amount of light emitted from regions of density due to self illumination. The The particular color selected from this range is determined by the Incandescence Input parameter. Incandescent emission is not affected by illumination or shadowing.

incandescence_Position (ip) float 0.0

Position of ramp value on normalized 0-1 scale

incandescence_Color (ic) float3

Ramp color at the sibling position

incandescence_ColorR (icr) float 0.0

Ramp red channel value at the sibling position

incandescence_ColorG (icg) float 0.0

Ramp green channel value at the sibling position

incandescence_ColorB (icb) float 0.0

Ramp blue channel value at the sibling position

incandescence_Interp (ii) enum 0

Ramp Interpolation controls the way the intermediate values are calculated. The values are:

None

Linear: The values are interpolated linearly in RGB color space.

Smooth: The values are interpolated along a bell curve, so that each color on the ramp dominates the region around it, then blends quickly to the next color.

Spline: The values are interpolated with a spline curve, taking neighboring indices into account for greater smoothness.

incandescenceInput (ili) enum 6

Defines a the attribute used to index the incandescence value. Constant sets the input to 1.0 or the end of the ramp. Color overrides the incandescence range using the value defined by the grid and the color scale. This is useful when using color emission into the grid. The other options all sets the input to corresponding value from the grid. For example if density is used the start of the color ramp will be used for density values of 0 and the end value for densities of 1.0. The way midrange values map out is determined by the Incandescence Input Bias

incandescenceInputBias (iib) float 0.0

Incandescence Input Bias adjusts the sensitivity of the selected incandescence input used. Input values of 0 and 1 will always map to the start and end of the ramp value, although the bias determines where in the ramp a value of 0.5 will index. For example if one used density as an input, and the material becomes relatively opaque at a density of 0.001, then the density bias can be used to shift most of the ramp into this density range. This is easier Instead of cramming several values at the beginning of the ramp one can use the full range. If the input bias is 0.0 then a value of 0.5 will map to the exact middle of the incandescence ramp.

glowIntensity (gi) float 0.0

Glow Intensity is 0 by default, meaning that no glow is added to the material. As this is turned up, the material seems to 'glow' with a faint halo of light around it.

Note that this is different from the Incandescence attribute in a few important ways. First, glow is added as a post-process at the end of rendering. (Incandescence just makes the surface appear brighter.) Second, glow adds a halo, which incandescence does not.

specularColor (spc) float3

Specular controls the amount of light emitted from regions of density due to self illumination.

specularColorR (spr) float 0.0

specular red value

specularColorG (spg) float 0.0

specular green value

specularColorB (spb) float 0.0

specular blue value

cosinePower (csp) float 20.0

Cosine Power is used to control the "tightness" of the specular highlights (also called 'hot spots') on the surface. The minimum value is 2. The higher the value, the more tighly focussed (smaller) is the highlight.

environment (env) compound n/a

Environment defines a simple sky to ground environmental reflection using a ramp. The left of the ramp is the top of the sky and the right is the bottom.

environment_Position (envp) float 0.0

Position of ramp value on normalized 0-1 scale

environment_Color (envc) float3

Ramp color at the sibling position

environment_ColorR (envcr) float 0.0

Ramp red channel value at the sibling position

environment_ColorG (envcg) float 0.0

Ramp green channel value at the sibling position

environment_ColorB (envcb) float 0.0

Ramp blue channel value at the sibling position

environment_Interp (envi) enum 0

Ramp Interpolation controls the way the intermediate values are calculated. The values are:

None

Linear: The values are interpolated linearly in RGB color space.

Smooth: The values are interpolated along a bell curve, so that each color on the ramp dominates the region around it, then blends quickly to the next color.

Spline: The values are interpolated with a spline curve, taking neighboring indices into account for greater smoothness.

dropoffShape (dos) enum 2

Defines a shape to use to define an outer boundary for creating a soft edged volume. If one is rendering a box volume then Cube should match the edges of the volume. Likewise for Sphere and Cone volumes.

edgeDropoff (edr) float .05

Defines the rate at which the density drops off towards the edge defined by the Dropoff Shape.

contrastTolerance (ctl) float 0.01

The maximum contrast in effective transparency of a volume span allowed by the adaptive subdivision sample method. When the contrast between two spans is greater than this value we subdivide the span. The contrast is defined as the effective difference in accumulated transparency from the viewpoint. If this value is high, then the sampling will look like uniform sampling. If the contrastTolerance is low then the quality will improve and the render time will increase, although we will not require as many samples as uniform sampling for a given render quality. The quality setting should be just high enough that one does not miss dense regions altogether( this creates artifacts like dotty fringes around clouds ).

heightField (hfld) bool false

If this is on then we draw a 2D surface as a heightfield rather than a flat plane. The opacity value is mapped to the height.

surfaceRender (srr) bool false

If this is on then we draw a surface instead of a soft volume. Shaded Display must be set to AsRender in order to see the surface in the interactive draw, or the outMesh must have a connection. The surface location is determined by the current opacity combined with the surface threshold.

surfaceThreshold (srt) float 0.01

Threshold value used to generate implicit surface

surfaceTolerance (stl) float 0.1

This determines how close points sampled for a surface lie to the the exact surfaceThreshold density. The quality setting should be made just high enough that we do not miss regions containing the surface. The render then further refines the surface using this tolerance. If this is high then the surface will look dotty and of poor quality. Very low values will result in longer render times and better quality. The tolerance value is defined relative to the quality setting. The quality determines the uniform step size, so that the actual distance this defines is equal to the step size * surfaceTolerance. This attribute is only for volume rendering of the fluid surface, and does not affect the fluid output mesh.

softSurface (ssf) bool false

This takes internal density variations into account when doing surface renders. If soft surface is on then the inside of the density will not be a constant substance like glass but rather a continuously varying density such as a cloud.

meshSmoothingIterations (msit) integer 0

This specifies how much to smooth the output mesh

meshMethod (mmd) enum 0

This determines what method is used to mesh the fluid isosurface

meshResolution (mre) float 2.0

This determines how finely the fluid is sampled when generating a mesh( convert fluid to poly). At a value of of 1.0 it only samples the fluid at voxels centers, which is the most efficient to compute. For higher values it increases the the grid resolution used for generating the output mesh, which will be slower but will more accurately resolve the fluid density, especially if there is an opacity texture. Also the output mesh will have more triangles when this attribute is higher. As well larger values will consume more memory. Values lower than 1.0 may be used, but it would in most cases be more efficent to instead lower the base fluid resolution.

colorPerVertex (cpvx) bool false

If on, then we create a color per vertex set name colorPV for the output mesh. This requires the use of a color per vertex texture to render on the mesh.

opacityPerVertex (opvx) bool false

If on, then we create a color per vertex set name opacityPV for the output mesh that is derived from the particle opacity values. This requires the use of a color per vertex texture to render on the mesh.

incandescencePerVertex (ipvx) bool false

If on, then we create a color per vertex set name incandesencePV for the output mesh that is derived from the particle incandescence values. This requires the use of a color per vertex texture to render on the mesh.

velocityPerVertex (vpvx) bool true

If on, then we create a color per vertex set name velocityPV for the output mesh that is derived from the fluid velocity values, where velocity xyz maps to color rgb. This is primarily for purposes of motion blur, which can be enabled by setting the attribute motionVectorColorSet to "velocityPV" on the fluid output mesh. (currently this only works for Mental Ray) The fluid output mesh typically changes topology over time which creates problem for the normal motion blur mechanism, which relies on comparing vertex positions at different points in time. With a topology changing mesh a vertex may not exist for all of the time samples causing the motion blur to fail. The velocityPV is computed directly from the fluid velocities and thus does not have this problem.

uvwPerVertex (upvx) bool false

If on, then we create a uvw per vertex set name uvwPV for the output mesh that is derived from the fluid uvw values. The uvw values will only move when the coordinateMethod is set to dynamic grid. In addition to the uvw color set the uv coordinates for the vertices will enabled, allowing one to apply a 2D texture to the mesh.

useGradientNormals (ugn) bool false

If on, then we create user normals based on the direction of the opacity gradient in the fluid. This results in a smoother looking output mesh, especially in regions with thin triangles. This only affects the output mesh of the fluid( convert fluid to poly ).

refractiveIndex (rei) float 1.8

Index of refraction. This property affects how reflectivity changes with viewing angle. It makes use of Fresnel's law. Materials with a low refractive index are generally only reflective at glancing angles. This is useful for a wet look or for water, because water has a lower refractive index than most solids. At a refractive index of 1.0 the material is considered to be the same as the medium, and theoretically there should be no specularity in this case( as with a cloud ). However we turn on full specularity in this case (ie. no view angle modulation), for convenience.

sampleMethod (smpm) enum 3

Controls how fluid is sampled during rendering Jitter avoids banding artifacts, but adds noise to the final image unless the quality is set high.

realLights (rl) bool true

Determines whether to use normal lights or a single built in directional light. The simple built in lighting is faster, especially for self shadowing, and it does not cast shadows or light onto other objects. Nor does it receive shadows from other objects.

pointLight (poli) float3

PointLight is the position of the internal point light used when RealLights is off.

pointLightX (polx) float 0.0

pointLight X value

pointLightY (poly) float 0.0

pointLight Y value

pointLightZ (polz) float 0.0

pointLight Z value

directionalLight (dl) float3

DirectionalLight is the direction of the internal directional light used when RealLights is off.

directionalLightX (dlx) float 0.5

directionalLight X value

directionalLightY (dly) float 0.8

directionalLight Y value

directionalLightZ (dlz) float 0.5

directionalLight Z value

textureType (tty) enum 0

Determines how to texture the volume's density. Perlin Noise is the standard 3D noise used in the solidFractal texture. Billow has a pluffy, cloudlike effect. Wispy is a perlin noise that uses a second noise as a smear map. This makes the noise stretch out in places, looking wispy. When the time attribute is animated the smear noise is moved causing an undulating effect. Volume Wave is a sum of 3D waves in space. SpaceTime is a 4 dimensional version of the perlin noise, where time is the 4th dimension. Mandelbrot is a non-random iterative function that yields complex structure.

colorTexture (ctx) bool false

Color Texture toggles the application of the current texture( determined by the texture type ) to the color input value.

colorTexGain (ctxg) float 1.0

Color Tex Gain determines how much the texture affects the input value to the color. If the color range is red to blue, then texturing will cause red to blue variations. At a value of zero there will be no color texturing.

incandTexture (itx) bool false

Incand Texture toggles the application of the current texture( determined by the texture type ) to the incandescence input value.

incandTexGain (itxg) float 1.0

Incand Tex Gain determines how much the texture affects the input value to the incandescence. If the incandescence range is red to blue, then texturing will cause red to blue variations. At a value of zero there will be no incandescence texturing.

opacityTexture (otx) bool false

Opacity Texture toggles the application of the current texture( determined by the texture type ) to the opacity input value.

opacityTexGain (otxg) float 1.0

Opacity Tex Gain determines how much the texture affects the input value to the opacity. If the opacity curve goes from 0.0 to 0.6, then texturing will cause variations between these values. At a value of zero there will be no opacity texturing.

invertTexture (ivt) bool false

InvertTexture This reverses the range of the texture so that dense regions become thin and thin become dense. If it is on, then the texture = 1 - texture.

amplitude (a) float 1.0

Amplitude is a scaling factor applied to all the values in the texture, centered around the texture's average value. This means that when you increase Amplitude, the light areas get lighter and the dark areas get darker.

If the Volume Noise is being used as a bump map, then increasing Amplitude will make the bumps higher and the valleys deeper.

If you set Amplitude to a value greater than 1.0, then those parts of the texture that scale out of range will be clipped. On a bump map, this will show up as plateau regions.

ratio (ra) float 0.707

Ratio controls the frequency of the fractal noise. Increase this value to increase the fineness of detail in the fractal,

threshold (th) float 0.0

Threshold is a number that is added to the whole fractal, making it uniformly brighter. If some parts of the fractal are pushed up out of range (greater than 1.0), then they will be clipped to 1.0. If the Volume Noise is being used as a bump map, this will show up as plateau regions.

textureScale (txsc) float3 1.0, 1.0, 1.0

Texture Scale determines the scale of the noise in the local x,y and z directions. It has a similar to scaling the transform node for the texture.

If you increase Scale in any particular direction, the fractal detail will seem to smear out in that direction.

textureScaleX (tscx) float 0.0

Scale X value

textureScaleY (tscy) float 0.0

Scale Y value

textureScaleZ (tscz) float 0.0

Scale Z value

textureOrigin (tor) float3 0.0, 0.0, 0.0

Texture Origin is the zero point for the noise. changing this value translates the noise through space.

textureOriginX (torx) float 0.0

Origin X value

textureOriginY (tory) float 0.0

Origin Y value

textureOriginZ (torz) float 0.0

Origin Z value

textureRotate (trt) float3 0.0, 0.0, 0.0

Texture Rotate controls the rotation of the texture about the fluid center.

textureRotateX (trtx) float 0.0

Rotate X value

textureRotateY (trty) float 0.0

Rotate Y value

textureRotateZ (trtz) float 0.0

Rotate Z value

depthMax (dm) short 2

DepthMax controls how much calculation is done by the Volume Noise texture. Fractal textures are created by an iterative mathematical process; as the process goes over more levels, it produces a more detailed fractal, but takes longer to do so. Normally, the texture will choose a level it thinks is appropriate for the volume being rendered. You can use Depth Max to control the maximum amount of calculation that the texure will do.

frequency (fq) float 1.0

Frequency This determines the fundamental frequency for the noise. As this value increases the noise becomes more detailed. It has the inverse effect of the scale parameter.

frequencyRatio (fr) float 2.0

Frequency Ratio This determines the relative spacial scale of the noise frequencies. If this ratio is not a whole integer then the fractal will not repeat at the integer uv boundaries. A cylinder with default placement would then display a seam.

inflection (in) bool false

Inflection This applies a kink in the noise function This is useful for creating puffy or bumpy effects. It is equivalent to abs(noise) * 2 - 1.

textureTime (tti) float 0.0

Texture Time is used to animate the Noise texture. You can keyframe the Time attribute to control the rate and amount of change of the texture. Typing the expression "= time" into the edit cell will cause the texture to billow when rendered in an animation. Typing "= time * 2" will make it billow twice as fast.

billowDensity (bd) float 1.0

Billow Density controls how many cells there are imbedded in the medium used by the Billow noise type. At 1.0, the medium is completely packed with cells. Reduce this value to make the cells more sparse.

If the texture is being used as a bump map, then low values for Density will make it look like a smooth surface with occasional bumps on it.

spottyness (sp) float 0.1

Spottyness controls the randomization of the density of the individual cells used by the Billow noise type. When Spottyness is close to 0, all the cells will be the same density. As you increase Spottyness, some cells will be denser or thinner than others, in a random fashion.

sizeRand (sr) float 0.0

Size Rand controls the randomization of the size of the individual blobs used by the Billow noise type. When it is close to 0, all the cells will be the same size. As you increase Size Rand, some cells will be smaller than others, in a random fashion.

randomness (rnd) float 1.0

Randomness controls how the cells for the Billow noise type are arranged relative to one another. Set randomness to 1.0 to get a realistic random distribution of cells, as would be found in nature. If you set Randomness to 0, all the spots are laid out in a completely regular pattern. This can provide interesting effects when used as a bump map; you can make things like insect eyes, or machine-tooled raspy surfaces.

falloff (falo) enum 2

This controls the way intensity falls off for individual blobs for the Billow noise type. Linear is a uniform falloff from the center to a value of zero at the edges of the blobs.Smooth is more natural looking, using a gaussian falloff. Fast focuses the intensity more towards the center of the blobs. Bubble uses a reverse falloff, fading to zero at the blob center.

numWaves (nw) short 5

NumWaves determines how many waves to generate for the VolumeWave noise type. The larger this number the more random looking and slower the texture.

implode (imp) float 0.0

Implode warps the noise function in a concentric fashion about a point defined by the Implode Center. At a value of zero there is no effect, while at a value of 1.0 it is a spherical projection of the noise function, creating a starburst effect. Negative values can be used to skew the noise outward instead of inward.

implodeCenter (imc) float3 0.0, 0.0, 0.0

Implode Center defines the center point about which the implode effect is defined.

implodeCenterX (imx) float 0.0

Implode Center X x position for implode effect

implodeCenterY (imy) float 0.0

Implode Center Y y position for implode effect

implodeCenterZ (imz) float 0.0

Implode Center Z z position for implode effect

mandelbrotDepth (mdm) integer 7

Depth controls how much calculation is done by the Mandelbrot texture. Fractal textures are created by an iterative mathematical process; as the process goes over more levels, it produces a more detailed fractal, but takes longer to do so. As one zooms in on the fractal higher depthMax values are required. The higher the depth the closer one can resolve the border region of the mandelbrot set.

focus (foc) float 1.0

Focus determines how tightly the colors map to the set. For close up zooms a higher focus can help push the colors closer to the boundary of the set.

zoomFactor (zfc) float 1.0

Zoom Factor is the level of magnification for the mandelbrot texture. The actual zoom is 2 raised to the power of the zoom factor. Thus a zoomFactor of 2 creates a zoom of 4 (2*2), while a zoomFactor of 3 would create a zoom of 8 (2*2*2). This results in a unform rate of zoom.

escapeRadius (esr) float 2.0

When the excapeRadius is exceeded the iteration on the mandelbrot function stops. For the classic set a value greater than two will guarantee the set is accurate as when that value is exceeded it is in the set and further iterations will tend to infinity. However for some variations on the set, higher iterations can be useful. With the checker effect higher values will result in closer together bands. As well values lower than 2 can also be used to create interesting effects.

lobes (lbs) float 1.0

Lobes controls the exponent used by the mandelbrot set. Higher powers create more lobes. The standard mandelbrot set is power 2 and results in 1 lobe. Increasing the lobe value will create more lobes and compute a set using a higher exponent.

leafEffect (lef) float 0.0

Leaf Effect thresholds the mandelbrot function in a way that creates the look of leaves.

checker (chk) float 0.0

Checker creates alternating regions. The tightness of the checker pattern is affected by the escapeRadius.

lineBlending (lbl) bool false

Line Blending creates smooth junctions between circles and stalks. It multiplies the values within iterations instead of taking the closest distance.

lineFocus (lfc) float 0.5

Line Focus controls the sharpness of the circle and stalk lines. They become thinner as this value increases.

points (pts) float 0.0

Points controls the intensity of shading based on distance to points each iteration. The offset UV value controls the position of the points. to create a stem-like structure.

stalksU (stku) float 0.0

StalksU controls the effect known as Pickover stalks where the distance to the axis is used to create a stem-like structure. The offset uv shifts the axis position used.

stalksV (stkv) float 0.0

StalksV controls the effect known as Pickover stalks where the distance to the axis is used to create a stem-like structure. The offset uv shifts the axis position used.

circles (cir) float 0.0

Circles creates a circle within each iteration in a manner similar to pickover stalks.

circleRadius (ccr) float 0.5

Circle Radius controls the size of the circles.

circleSizeRatio (csr) float 1.0

Circle Size Ratio controls the rate at which the circle radius changes each iteration.

lineOffsetU (lou) float 0.0

LineOffsetU shifts the location of points, circles and stalks.

lineOffsetV (lov) float 0.0

LineOffsetU shifts the location of points, circles and stalks.

lineOffsetRatio (lor) float 1.0

Line Offset Ratio controls the rate at which the line offset changes each iteration. The line offset u or v should be non-zero for this to have an effect, as it multiplies those values within each iteration.

juliaU (jlu) float 0.0

JuliaU is the first component of the of the complex number used to define the Julia set. This may be thought of as a coordinate in the complex plane. The full mandelbrot set automatically sets this coordinate to the uv coordinate and it thus contains all possible Julia sets. For a Julia set, however, one must specify this coordinate manually.

juliaV (jlv) float 0.0

JuliaV is the second or imaginary component of the complex number used to define the Julia set. This may be thought of as a coordinate in the complex plane. The full mandelbrot set automatically sets this coordinate to the uv coordinate and it thus contains all possible Julia sets. For a Julia set, however, one must specify this coordinate manually.

boxRadius (bxr) float 1.0

Box Radius controls the primary radius within each iteration for the mandebox and hybrid methods.

boxMinRadius (bxm) float 0.5

Box Min Radius controls the minimum radius within each iteration for the mandebox and hybrid methods.

boxRatio (brt) float -3.0

Box Ratio controls the amount the radius is scaled each iteration, which determines the ratio of sizes between iterations.

mandelbrotType (nty) enum 1

Determines the overall type of fractal simulation to use. Julia Set can be used to create swirling self similar patterns. It has two input variables JuliaU and JuliaV that control its shape. Mandebrot Set is the standard mandelbrot set. It contains all possible Julia sets, mapping the two variables of the Julia set to the input UV positions. The 3D form is referred to as the Mandelbulb, and this will tend to look better when using a higher values for the lobes setting. Mandelbox is a recursive folding operation that creates interesting geometric patterns. It can create shapes that look less organic and more man made than the mandelbrot function. There are 3 parameters that control the function: boxRadius, boxMinRadius, and boxRatio. Some values for these attributes may be very chaotic while others can create regular patterns. Box with Julia Set is a combination of both the julia set function and the mandelbox. It may be thought of as a mirroring or folding of the set as it iterates. A wide variety of patterns are possible by varying the mandelbox parameters along with the julia uv attributes. Box with Mandelbrot Set combines the mandelbox and mandelbrot functions.

mandelbrotShadeMethod (msm) enum 1

Determines how to shade the mandelbrot structure. Classic shades based on the total number of iterations before the escape radius is exceeded. Smooth is like the classic set but creates a continuous range of values with no banding. Minimum Radius shades based on the smallest radius within all iterations Escape Radius shades based on the radius in the final iteration Lines Only Only draws the points stalks and circles with no background set.

mandelbrotInsideMethod (mim) enum 2

Determines how to shade the base mandelbrot set for regions that fall inside the set. Zero sets regions inside the set to a fixed zero value. Max Iteration shades inside areas with the max iteration. This matches the inside edge when used as a displacement map. Shaded Inside does a smooth shading of internal values based on the radius. Shaded WithoutLines does a smooth shading of internal values based on the radius but the effect of points, circles and stalks are only on the outside. Lines applies lines on the inside but no other shading. Inner Lines Only applies lines on the inside but not to regions outside the set.

outColor (ocl) float3 0.0, 0.0, 0.0

The fog output color.

outColorR (ocr) float 0.0

The red component of the fog output color.

outColorG (ocg) float 0.0

The green component of the fog output color.

outColorB (ocb) float 0.0

The blue component of the fog output color.

outGlowColor (ogc) float3

Out Glow Color is the final output glow color from this node (if this node is glowing)

outGlowColorR (ogr) float 0.0

out glow color red value

outGlowColorG (ogg) float 0.0

out glow color green value

outGlowColorB (ogb) float 0.0

out glow color blue value

outTransparency (ot) float3 0.0, 0.0, 0.0

The fog output transparency.

outTransparencyR (otr) float 0.0

The red component of the fog output transparency.

outTransparencyG (otg) float 0.0

The green component of the fog output transparency.

outTransparencyB (otb) float 0.0

The blue component of the fog output transparency.

outMatteOpacity (omo) float3

output Matte Opacity

outMatteOpacityR (omor) float 0.0

output Matte Opacity red value

outMatteOpacityG (omog) float 0.0

output Matte Opacity green value

outMatteOpacityB (omob) float 0.0

output Matte Opacity blue value

diskCache (dc) Message n/a

Connection for playback cache node

diskCacheIC (dcic) Message n/a

Connection for initial conditions node

cacheDensity (cdns) bool true

During cache creation, if this object has a density grid write the grid to the disk cache

loadDensity (ldns) bool true

When reading from a cache, if the cache contains a density grid read the density from the cache

cacheVelocity (cvel) bool true

During cache creation, if this object has a velocity grid write the grid to the disk cache

loadVelocity (lvel) bool true

When reading from a cache, if the cache contains a velocity grid read the velocity from the cache

cacheTemperature (ctmp) bool true

During cache creation, if this object has a Temperature grid write the grid to the disk cache

loadTemperature (ltmp) bool true

When reading from a cache, if the cache contains a Temperature grid read the temperature from the cache

cacheColor (ccol) bool true

During cache creation, if this object has a Color grid write the grid to the disk cache

loadColor (lcol) bool true

When reading from a cache, if the cache contains a Color grid read the color from the cache

cacheReaction (crea) bool true

During cache creation, if this object has a Reaction grid write the grid to the disk cache

loadReaction (lrea) bool true

When reading from a cache, if the cache contains a Fuel grid read the fuel from the cache

cacheTextureCoordinates (catc) bool true

During cache creation, if this object has a Texture Coordinate grid write the grid to the disk cache

loadTextureCoordinates (lotc) bool true

When reading from a cache, if the cache contains a Texture Coordinate grid read the grid from the cache

cacheFalloff (cfal) bool true

During cache creation, if this object has a falloff grid write the grid to the disk cache

loadFalloff (lfal) bool true

When reading from a cache, if the cache contains a falloff grid read the falloff from the cache

playFromCache (pfch) bool false

When enabled, it reads back position from the vector array input

inResolution (ires) floatArray NULL

Input for cached resolution data

inOffset (ioff) floatArray NULL

Input for cached dynamic offset data

inDensity (idns) floatArray NULL

Input for cached density data

inVelocity (ivel) floatArray NULL

Input for cached velocity data

inTemperature (itmp) floatArray NULL

Input for cached temperature data

inReaction (irea) floatArray NULL

Input for cached fuel data

inColor (icol) floatArray NULL

Input for cached color data

inTextureCoordinates (itxc) floatArray NULL

Input for cached texture coordinate data

inFalloff (ifal) floatArray NULL

Input for cached falloff data

collisionData (cda) compound n/a

Parent attribute for all collision input data.

collisionGeometry (cge) sweptGeometry NULL

The swept geometry for the connected shape.

collisionResilience (crs) double 0.0

How much of the particle's velocity perpendicular to the surface is reflected

collisionFriction (cfr) double 0.0

The amount of a particle's velocity parallel to a surface that is lost in the collision

collide (cld) bool true

A toggle to turn enable collision of fluid flow with attached geometry.

objectType (obt) char TrenderableObjectType::kVolume

The type of object being shaded.

surfaceShaderDepth (susd) float 1.0

Surface Shader Depth controls how far in worldspace beyond a surface that we compute the fluid when used as a shader for surfaces(nurbs and polysets).

particleWeight (we) float 0.0

the weight in the intensity calculation

coordinateSpeed (csd) float 0.2

This parameter scales how fast coordinates are moved by the velocity when the coordinate method is GRID. At a value of 1.0 the coordinates are pushed through the volume at the same speed as the other contents, such as density. However this tends to result in the texture becoming smeared out after a few steps. Lower values tend to preserve the character of the texture and can look more natural. Animating this value can be useful in some situations, such as when one does not wish the texture to deform before a certain point( keyframe it to zero until the desired start point ).