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MFnFluid Class Reference

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Detailed Description

Fluid node function set.

This is the function set for fluid objects.

A fluid object is a node in the dependency graph that contains a grid which is made up of cells. Each cell has a variety of values assigned to it such as density, velocity, temperature, and color. The grid may be 2D or 3D. See the methods below for full details.

Fluid objects may be used for simulation purposes. This function set allows read and write access to the values in the cells of the fluid object.

Examples:

fluidInfoCmd.cpp, simpleFluidEmitter.cpp, and simpleFluidEmitter.h.

#include <MFnFluid.h>

Inheritance diagram for MFnFluid:
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List of all members.

Public Types

enum  FluidMethod { kZero, kStaticGrid, kDynamicGrid, kGradient }
 

Defines how voxel values are computed for most types of fluid data.

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enum  FluidGradient {
  kConstant, kXGradient, kYGradient, kZGradient,
  kNegXGradient, kNegYGradient, kNegZGradient, kCenterGradient
}
 

Defines the orientation of the gradient.

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enum  FalloffMethod { kNoFalloffGrid, kStaticFalloffGrid }
 

Falloff data only supports a subset of the available fluid methods.

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enum  ColorMethod { kUseShadingColor, kStaticColorGrid, kDynamicColorGrid }
 

Color data has its own set of methods for computing voxel data.

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enum  CoordinateMethod { kFixed, kGrid }
 

Coordinate data has its own set of methods for computing voxel data.

More...

Public Member Functions

virtual MFn::Type type () const
 Function set type.
virtual ~MFnFluid ()
 Destructor.
 MFnFluid ()
 Default constructor.
 MFnFluid (MObject &object, MStatus *ReturnStatus=NULL)
 Constructor.
 MFnFluid (const MDagPath &object, MStatus *ret=NULL)
 Constructor.
MObject create3D (unsigned int Xres, unsigned int Yres, unsigned int Zres, double Xdim, double Ydim, double Zdim, MObject parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
 Creates a fluid object from the specified data and sets this function set to operate on the new fluid object.
MObject create2D (unsigned int Xres, unsigned int Yres, double Xdim, double Ydim, MObject parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
 Creates a fluid object from the specified data and sets this function set to operate on the new fluid object.
MStatus getResolution (unsigned int &Xres, unsigned int &Yres, unsigned int &Zres) const
 Gets the resolution of the fluid.
MStatus getResolution (unsigned int &Xres, unsigned int &Yres) const
 Gets the resolution of the fluid.
MStatus getDimensions (double &Xdim, double &Ydim, double &Zdim) const
 Gets the dimensions of the fluid.
MStatus setSize (unsigned int Xres, unsigned int Yres, unsigned int Zres, double Xdim, double Ydim, double Zdim, bool resample)
 Sets the size and resolution of the grid.
MStatus setSize (unsigned int Xres, unsigned int Yres, double Xdim, double Ydim, bool resample)
 Sets the size and resolution of the grid.
unsigned int gridSize (MStatus *ReturnStatus=NULL)
 Returns the number of elements in the grid.
MStatus velocityGridSizes (int &xsize, int &ysize, int &zsize)
 Returns the number of elements in the velocity grids.
float * falloff (MStatus *ReturnStatus=NULL)
 This method returns a pointer to the storage for the falloff data in the fluid.
float * density (MStatus *ReturnStatus=NULL)
 This method returns a pointer to the storage for the density data in the fluid.
MStatus getVelocity (float *&Xvel, float *&Yvel, float *&Zvel)
 This method returns pointers to the storage for the velocity data in the fluid.
float * pressure (MStatus *ReturnStatus=NULL)
 This method returns a pointer to the storage for the pressure data in the fluid.
float * temperature (MStatus *ReturnStatus=NULL)
 This method returns a pointer to the storage for the temperature data in the fluid.
float * fuel (MStatus *ReturnStatus=NULL)
 This method returns a pointer to the storage for the fuel data in the fluid.
MStatus getCoordinates (float *&u, float *&v, float *&w)
 This method returns pointers to the storage for the uvw coordinate data in the fluid.
MStatus getColors (float *&r, float *&g, float *&b)
 This method returns pointers to the storage for the color data in the fluid.
MStatus setFalloffMode (FalloffMethod mode)
 Set the modes by which the shader falloff values in the grid are determined.
MStatus getFalloffMode (FalloffMethod &mode)
 Get the modes by which the falloff values in the grid are determined.
MStatus setDensityMode (FluidMethod mode, FluidGradient gradient)
 Set the modes by which the density values in the grid are determined.
MStatus getDensityMode (FluidMethod &mode, FluidGradient &gradient)
 Get the modes by which the density values in the grid are determined.
MStatus setVelocityMode (FluidMethod mode, FluidGradient gradient)
 Set the modes by which the velocity values in the grid are determined.
MStatus getVelocityMode (FluidMethod &mode, FluidGradient &gradient)
 Get the modes by which the velocity values in the grid are determined.
MStatus setTemperatureMode (FluidMethod mode, FluidGradient gradient)
 Set the modes by which the temperature values in the grid are determined.
MStatus getTemperatureMode (FluidMethod &mode, FluidGradient &gradient)
 Get the modes by which the temperature values in the grid are determined.
MStatus setFuelMode (FluidMethod mode, FluidGradient gradient)
 Set the modes by which the fuel values in the grid are determined.
MStatus getFuelMode (FluidMethod &mode, FluidGradient &gradient)
 Get the modes by which the fuel values in the grid are determined.
MStatus setCoordinateMode (CoordinateMethod mode)
 Set the modes by which the UVW coordinate values in the grid are determined.
MStatus getCoordinateMode (CoordinateMethod &mode)
 Get the modes by which the UVW coordinates values in the grid are determined.
MStatus setColorMode (ColorMethod mode)
 Set the modes by which the color values in the grid are determined.
MStatus getColorMode (ColorMethod &mode)
 Get the modes by which the color values in the grid are determined.
MStatus getForceAtPoint (const MPointArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime=1.0/24.0)
 Compute the force of the fluid as a field on an array of points, given their position, velocity, and mass.
MStatus getForceAtPoint (const MVectorArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime=1.0/24.0)
 Compute the force of a field on an array of points, given their position, velocity, and mass.
bool toGridIndex (const MPoint &objectSpacePoint, int3 &gridCoords, MStatus *status=NULL)
 For the given point in object space, get the grid indices of the voxel that it happens to lie in.
MStatus voxelCenterPosition (int xi, int yi, int zi, MPoint &objectSpacePoint)
 For the given voxel, get the location of the center in object space.
MStatus updateGrid ()
 Tells the fluid shape that the contents of the fluid grid has changed.
void emitIntoArrays (float val, int x, int y, int z, float density, float heat, float fuel, bool doColor, const MColor &emitColor)
 Use this method to add density, heat, fuel, and/or color to a particular voxel of a fluid.
int index (int xi, int yi)
 This is a utility routine for finding the index of a cell in an array of fluid data.
int index (int xi, int yi, int zi)
 This is a utility routine for finding the index of a cell in an array of fluid data.
void index (int ai, int &xi, int &yi, int &zi)
 This is a utility routine for finding the coordinates of a cell in an array of fluid data given the index.
int index (int xi, int yi, int zi, int xres, int yres, int zres)
 This is a utility routine for finding the index of a cell given the X, Y and Z resolutions.
void index (int ai, int xres, int yres, int zres, int &xi, int &yi, int &zi)
 This is a utility routine for finding the coordinates of a cell given the index, and the X, Y and Z resolutions.
 MFnFluid (const MObject &object, MStatus *ret=NULL)
 Constructor.

Protected Member Functions

virtual const char * className () const
 Class name.

Member Enumeration Documentation

Defines how voxel values are computed for most types of fluid data.

Enumerator:
kZero 

All values in grid are zero.

kStaticGrid 

Values in the grid are static.

kDynamicGrid 

Values in the grid come from a dynamic solver.

kGradient 

Ramps the value based on the gradient setting.

Defines the orientation of the gradient.

Enumerator:
kConstant 

Value is set to one across the volume.

kXGradient 

Ramp the value from zero to one along the X axis.

kYGradient 

Ramp the value from zero to one along the Y axis.

kZGradient 

Ramp the value from zero to one along the Z axis.

kNegXGradient 

Ramp the value from one to zero along the X axis.

kNegYGradient 

Ramp the value from one to zero along the Y axis.

kNegZGradient 

Ramp the value from one to zero along the Z axis.

kCenterGradient 

Ramps the value from one at the center to zero at the edges.

Falloff data only supports a subset of the available fluid methods.

Enumerator:
kNoFalloffGrid 

No falloff grid should be defined.

kStaticFalloffGrid 

Values in the falloff grid are static.

Color data has its own set of methods for computing voxel data.

Enumerator:
kUseShadingColor 

Off, use shading color instead.

kStaticColorGrid 

Values in the grid are static.

kDynamicColorGrid 

Values in the grid come from a dynamic solver.

Coordinate data has its own set of methods for computing voxel data.

Enumerator:
kFixed 

Values are equal the object space coordinates.

kGrid 

Coordinate values will be moved using the current density solver.


Constructor & Destructor Documentation

MFnFluid ( MObject object,
MStatus ReturnStatus = NULL 
)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters:
[in]objectThe MObject to attach the function set to
[out]ReturnStatusthe return status
Status Codes:
MFnFluid ( const MDagPath object,
MStatus ReturnStatus = NULL 
)

Constructor.

Class constructor that initializes the function set to the given constant MDagPath object.

Parameters:
[in]objectThe const MDagPath to attach the function set to
[out]ReturnStatusThe return status
Status Codes:
MFnFluid ( const MObject object,
MStatus ReturnStatus = NULL 
)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters:
[in]objectThe MObject to attach the function set to
[out]ReturnStatusthe return status
Status Codes:

Member Function Documentation

MFn::Type type ( ) const [virtual]

Function set type.

Return the class type : MFn::kFluid.

Reimplemented from MFnDagNode.

const char * className ( ) const [protected, virtual]

Class name.

Return the class name : "MFnFluid".

Reimplemented from MFnDagNode.

MObject create3D ( unsigned int  Xres,
unsigned int  Yres,
unsigned int  Zres,
double  Xdim,
double  Ydim,
double  Zdim,
MObject  parent = MObject::kNullObj,
MStatus ReturnStatus = NULL 
)

Creates a fluid object from the specified data and sets this function set to operate on the new fluid object.

The parent argument is used to specify the DAG parent of the new fluid. If parent is NULL then a new transform will be created and returned which will be the parent for the new fluid shape. The new transform will be added to the DAG.

If parent is a DAG node then the new fluid will be returned and the parent passed in will become the new node's parent.

Parameters:
[in]Xresnumber of fluid grid cells in the x dimension
[in]Yresnumber of fluid grid cells in the y dimension
[in]Zresnumber of fluid grid cells in the z dimension
[in]Xdimobject space size in the x dimension
[in]Ydimobject space size in the y dimension
[in]Zdimobject space size in the z dimension
[in]parentspecifies what to do with the new fluid object. If a DAG object or NULL is given then a transform will be created for the new fluid shape and placed under the specified (optional)parent.
[out]ReturnStatusStatus code
Returns:
  • If parent is NULL then the transform for this fluid shape is returned
  • If parent is a DAG object then the new fluid shape is returned
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kValueOutOfRange A grid cell resolution or dimension parameter is invalid.
  • MS::kFailure An object error has occurred.
MObject create2D ( unsigned int  Xres,
unsigned int  Yres,
double  Xdim,
double  Ydim,
MObject  parent = MObject::kNullObj,
MStatus ReturnStatus = NULL 
)

Creates a fluid object from the specified data and sets this function set to operate on the new fluid object.

The parent argument is used to specify the DAG parent of the new fluid. If parent is NULL then a new transform will be created and returned which will be the parent for the new fluid shape. The new transform will be added to the DAG.

If parent is a DAG node then the new fluid will be returned and the parent passed in will become the new node's parent.

Parameters:
[in]Xresnumber of fluid grid cells in the x dimension
[in]Yresnumber of fluid grid cells in the y dimension
[in]Xdimobject space size in the x dimension
[in]Ydimobject space size in the y dimension
[in]parentspecifies what to do with the new fluid object. If a DAG object or NULL is given then a transform will be created for the new fluid shape and placed under the specified (optional)parent.
[out]ReturnStatusStatus code
Returns:
  • If parent is NULL then the transform for this fluid shape is returned
  • If parent is a DAG object then the new fluid shape is returned
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kValueOutOfRange A grid cell resolution or dimension parameter is invalid.
  • MS::kFailure An object error has occurred.
MStatus getResolution ( unsigned int &  Xres,
unsigned int &  Yres,
unsigned int &  Zres 
) const

Gets the resolution of the fluid.

The resolution gives the number of cells in the fluid grid in each direction.

Parameters:
[out]Xresstorage for returning the number of fluid grid cells in the x dimension
[out]Yresstorage for returning the number of fluid grid cells in the y dimension
[out]Zresstorage for returning the number of fluid grid cells in the z dimension
Returns:
Status code
Status Codes:
Examples:
simpleFluidEmitter.cpp.
MStatus getResolution ( unsigned int &  Xres,
unsigned int &  Yres 
) const

Gets the resolution of the fluid.

The resolution gives the number of cells in the fluid grid in each direction.

Parameters:
[out]Xresstorage for returning the number of fluid grid cells in the x dimension
[out]Yresstorage for returning the number of fluid grid cells in the y dimension
Returns:
Status code
Status Codes:
MStatus getDimensions ( double &  Xdim,
double &  Ydim,
double &  Zdim 
) const

Gets the dimensions of the fluid.

The dimensions give the object space size of the fluid object in each direction.

Parameters:
[out]Xdimstorage for returning the dimension of the fluid in x
[out]Ydimstorage for returning the dimension of the fluid in y
[out]Zdimstorage for returning the dimension of the fluid in z
Returns:
Status code
Status Codes:
Examples:
simpleFluidEmitter.cpp.
MStatus setSize ( unsigned int  Xres,
unsigned int  Yres,
unsigned int  Zres,
double  Xdim,
double  Ydim,
double  Zdim,
bool  resample 
)

Sets the size and resolution of the grid.

The resolution parameters control the number of cells in the fluid grid and the dimension parameters set the size of the fluid shape in object space.

Parameters:
[in]Xresnumber of fluid grid cells in the x dimension
[in]Yresnumber of fluid grid cells in the y dimension
[in]Zresnumber of fluid grid cells in the z dimension
[in]Xdimobject space size in the x dimension
[in]Ydimobject space size in the y dimension
[in]Zdimobject space size in the z dimension
[in]resampletrue if the previous contents of the grid should be scaled to fit the new size by resampling the previous data at the new resolution
Returns:
Status code
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kValueOutOfRange A grid cell resolution or dimension parameter is invalid.
  • MS::kFailure An object error has occurred. This can occur if this is called on a 2D fluid
MStatus setSize ( unsigned int  Xres,
unsigned int  Yres,
double  Xdim,
double  Ydim,
bool  resample 
)

Sets the size and resolution of the grid.

The resolution parameters control the number of cells in the fluid grid and the dimension parameters set the size of the fluid shape in object space.

Parameters:
[in]Xresnumber of fluid grid cells in the x dimension
[in]Yresnumber of fluid grid cells in the y dimension
[in]Xdimobject space size in the x dimension
[in]Ydimobject space size in the y dimension
[in]resampletrue if the previous contents of the grid should be scaled to fit the new size by resampling the previous data at the new resolution
Returns:
Status code
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kValueOutOfRange A grid cell resolution or dimension parameter is invalid.
  • MS::kFailure An object error has occurred. This can occur if this is called on a 2D fluid
unsigned int gridSize ( MStatus ReturnStatus = NULL)

Returns the number of elements in the grid.

This is equal to (x resolution * y resolution * z resolution). This routine is provided as a convenience to be used with the methods that give direct access to the fluid data. This gives the upper bound on the arrays. This size applies to all grids except for the 3 velocity grids.

Parameters:
[out]ReturnStatusStatus code.
Returns:
The number of elements.
Status Codes:
MStatus velocityGridSizes ( int &  xsize,
int &  ysize,
int &  zsize 
)

Returns the number of elements in the velocity grids.

X velocity size = (x resolution+1 * y resolution * z resolution). Y velocity size = (x resolution * y resolution+1 * z resolution). Z velocity size = (x resolution * y resolution * z resolution+1).

This routine is provided as a convenience to be used with the methods that give direct access to the velocity grids.

Parameters:
[out]xsizestorage for the x velocity grid size
[out]ysizestorage for the y velocity grid size
[out]zsizestorage for the z velocity grid size
Returns:
Status code
Status Codes:
float * falloff ( MStatus ReturnStatus = NULL)

This method returns a pointer to the storage for the falloff data in the fluid.

The size of this array can be obtained using the "gridSize" call.

The returned pointer points to an array of float values, each one representing the falloff value in a cell of the fluid grid. To get the array index corresponding to a cell index (x,y,z), use the "index" helper method.

If you modify the data via the pointer returned, you must call the "updateGrid" call or you will not see your changes.

Values from the falloff grid are used when the fluid's Falloff Shape attribute is set to "Grid". This mode allows users to specify arbitrary falloff values between 0 and 1 at each grid cell. At render time, the shaded opacity values of the fluid will be multiplied by the interpolated falloff grid value raised to the power of 1/(1-ed), where "ed" is the value of the fluid's "edgeDropoff" attribute. When edgeDropoff=0, the opacity multiplier is 1, and when edgeDropoff is 1, the opacity multiplier is 0. Assuming that falloff grid values are in the range [0,1], raising the edge dropoff value from 0 to 1 will cause the fluid opacity to smoothly fall off towards complete transparency.

Parameters:
[out]ReturnStatusStatus code
Returns:
Pointer to the float data of the grid
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's falloff mode is set to kNone
Examples:
simpleFluidEmitter.cpp.
float * density ( MStatus ReturnStatus = NULL)

This method returns a pointer to the storage for the density data in the fluid.

The size of this array can be obtained using the "gridSize" call.

The pointer returned points to an array of float values, each one representing the density value in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method.

If you modify the data via the pointer returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]ReturnStatusStatus code
Returns:
Pointer to the density data of the grid
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's density mode is set to kNone
MStatus getVelocity ( float *&  Xvel,
float *&  Yvel,
float *&  Zvel 
)

This method returns pointers to the storage for the velocity data in the fluid.

The size of these arrays can be obtained using the "gridSize" call.

Each of the pointers returned points to an array of float values, each value representing the velocity in a cell of the fluid grid . The three arrays contain the x components, y components, and z components of the velocity respectively.

The grid sizes are different for each of the velocity grids. The Xvel grid is one larger in X, the Yvel in Y, the Zvel in Z. This is because the velocity components are stored at the voxel face centers, not at the voxel centers. The index methods that specify the resolutions explicitly should be used for the velocity grids.

If you modify the data via the pointers returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]Xvelstorage for returning a pointer to the x components of the velocity values in the grid
[out]Yvelstorage for returning a pointer to the y components of the velocity values in the grid
[out]Zvelstorage for returning a pointer to the z components of the velocity values in the grid
Returns:
Status code
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's velocity mode is set to kNone
float * pressure ( MStatus ReturnStatus = NULL)

This method returns a pointer to the storage for the pressure data in the fluid.

The size of this array can be obtained using the "gridSize" call. Note that the pressure data only exists if the velocity method is kStaticGrid or kDynamicGrid

The pointer returned points to an array of float values, each one representing the pressure value in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method.

If you modify the data via the pointer returned, you must call the "updateGrid" call or you will not see your changes. Note that the pressure data is an output of the velocity calculation. if you modify the pressure grid and the velocity grid is dynamic, your changes will be replaced after the next fluid evaluation.

Parameters:
[out]ReturnStatusStatus code
Returns:
Pointer to the pressure data of the grid
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's velocity mode is set to kNone or kGradient
float * temperature ( MStatus ReturnStatus = NULL)

This method returns a pointer to the storage for the temperature data in the fluid.

The size of this array can be obtained using the "gridSize" call.

The pointer returned points to an array of float values, each one representing the temperature value in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method.

If you modify the data via the pointer returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]ReturnStatusStatus code
Returns:
Pointer to the temperature data of the grid
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's temperature mode is set to kNone
float * fuel ( MStatus ReturnStatus = NULL)

This method returns a pointer to the storage for the fuel data in the fluid.

The size of this array can be obtained using the "gridSize" call.

The pointer returned points to an array of float values, each one representing the fuel value in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method.

If you modify the data via the pointer returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]ReturnStatusStatus code
Returns:
Pointer to the fuel data of the grid
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's fuel method is set to kNone
MStatus getCoordinates ( float *&  u,
float *&  v,
float *&  w 
)

This method returns pointers to the storage for the uvw coordinate data in the fluid.

The size of these arrays can be obtained using the "gridSize" call. The uvw values supply the 3D texture mapping coordinates for each cell.

Each of the pointers returned points to an array of float values, each value representing the u, v, or w value in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method. The three arrays contain the u values, v values, and w values of the texture coordinates respectively.

For a 2D fluid, a NULL pointer will be returned for the w array.

If you modify the data via the pointers returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]ustorage for returning a pointer to the u values in the grid
[out]vstorage for returning a pointer to the v values in the grid
[out]wstorage for returning a pointer to the w values in the grid
Returns:
Status code
Status Codes:
MStatus getColors ( float *&  r,
float *&  g,
float *&  b 
)

This method returns pointers to the storage for the color data in the fluid.

The size of these arrays can be obtained using the "gridSize" call.

Each of the pointers returned points to an array of float values, each value representing the color in a cell of the fluid grid. To get the index of in the array for a cell at a given (x, y, z) use the "index" helper method. The three arrays contain the r components, g components, and b components of the color respectively.

If you modify the data via the pointers returned, you must call the "updateGrid" call or you will not see your changes.

Parameters:
[out]rstorage for returning a pointer to the red components of the color values in the grid
[out]gstorage for returning a pointer to the green components of the color values in the grid
[out]bstorage for returning a pointer to the blue components of the color values in the grid
Returns:
Status code
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure An object error has occurred. This may occur if the fluid's color mode is set to kNone
MStatus setFalloffMode ( MFnFluid::FalloffMethod  method)

Set the modes by which the shader falloff values in the grid are determined.

If the falloff grid is enabled, its values must be set by the user.

The method parameter may have the following values:

  • kNoFalloffGrid A constant value of 0.0 is used.
  • kStaticFalloffGrid Values in the grid are static
Parameters:
[in]methodmethod for determining the falloff value in the grid
Returns:
Status code
Status Codes:
MStatus getFalloffMode ( MFnFluid::FalloffMethod method)

Get the modes by which the falloff values in the grid are determined.

If the falloff grid is enabled, its values must be set by the user.

The method parameter may return the following values:

  • kNoFalloffGrid the shaders color is used
  • kStaticFalloffGrid Values in the grid are static
Parameters:
[out]methodstorage for returning the method by which the falloff value in the grid is determined
Returns:
Status code
Status Codes:
MStatus setDensityMode ( MFnFluid::FluidMethod  method,
MFnFluid::FluidGradient  gradient 
)

Set the modes by which the density values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may have the following values:

  • kZero sets the density to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method is set to be kGradient, then the gradient argument is also used. This deterines how a gradient is applied to the volume. The possible values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[in]methodmethod for determining the fluid density in the grid
[in]gradientgradient type, only used if the method is kGradient
Returns:
Status code
Status Codes:
MStatus getDensityMode ( MFnFluid::FluidMethod method,
MFnFluid::FluidGradient gradient 
)

Get the modes by which the density values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kZero sets the density to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method returns kGradient, then the gradient type is also returned. This deterines how a gradient is applied to the volume. The possible return values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[out]methodstorage for returning the method by which the fluid density in the grid is determined
[out]gradientstorage for returning the gradient type, which is only relevant if the method is kGradient
Returns:
Status code
Status Codes:
MStatus setVelocityMode ( MFnFluid::FluidMethod  method,
MFnFluid::FluidGradient  gradient 
)

Set the modes by which the velocity values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may have the following values:

  • kZero sets the velocity to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method is set to be kGradient, then the gradient argument is also used. This deterines how a gradient is applied to the volume. The possible values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[in]methodmethod for determining the fluid velocity in the grid
[in]gradientgradient type, only used if the method is kGradient
Returns:
Status code
Status Codes:
MStatus getVelocityMode ( MFnFluid::FluidMethod method,
MFnFluid::FluidGradient gradient 
)

Get the modes by which the velocity values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kZero sets the velocity to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method returns kGradient, then the gradient type is also returned. This deterines how a gradient is applied to the volume. The possible return values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[out]methodstorage for returning the method by which the fluid velocity in the grid is determined
[out]gradientstorage for returning the gradient type, which is only relevant if the method is kGradient
Returns:
Status code
Status Codes:
MStatus setTemperatureMode ( MFnFluid::FluidMethod  method,
MFnFluid::FluidGradient  gradient 
)

Set the modes by which the temperature values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may have the following values:

  • kZero sets the temperature to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method is set to be kGradient, then the gradient argument is also used. This deterines how a gradient is applied to the volume. The possible values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[in]methodmethod for determining the fluid temperature in the grid
[in]gradientgradient type, only used if the method is kGradient
Returns:
Status code
Status Codes:
MStatus getTemperatureMode ( MFnFluid::FluidMethod method,
MFnFluid::FluidGradient gradient 
)

Get the modes by which the temperature values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kZero sets the temperature to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method returns kGradient, then the gradient type is also returned. This deterines how a gradient is applied to the volume. The possible return values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[out]methodstorage for returning the method by which the fluid temperature in the grid is determined
[out]gradientstorage for returning the gradient type, which is only relevant if the method is kGradient
Returns:
Status code
Status Codes:
MStatus setFuelMode ( MFnFluid::FluidMethod  method,
MFnFluid::FluidGradient  gradient 
)

Set the modes by which the fuel values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation. The fuel value for a cell can be thought of as the amount of fuel contained in the cell that will be consumed during the simulation.

The method parameter may have the following values:

  • kZero sets the fuel to zero across the volume
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

Note that kStatic is not an option for the fuel mode. A static grid of fuel values would not make sense as the solver needs to use up the fuel during the simulation.

If the method is set to be kGradient, then the gradient argument is also used. This deterines how a gradient is applied to the volume. The possible values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[in]methodmethod for determining the fluid fuel in the grid
[in]gradientgradient type, only used if the method is kGradient
Returns:
Status code
Status Codes:
MStatus getFuelMode ( MFnFluid::FluidMethod method,
MFnFluid::FluidGradient gradient 
)

Get the modes by which the fuel values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kZero sets the fuel values to zero across the volume
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
  • kGradient ramps the value based on the gradient setting (see below)

If the method returns kGradient, then the gradient type is also returned. This deterines how a gradient is applied to the volume. The possible return values are as follows:

  • kConstant value is set to one across the volume
  • kXGradient ramp the value from zero to one along the X axis
  • kYGradient ramp the value from zero to one along the Y axis
  • kZGradient ramp the value from zero to one along the Z axis
  • kNegXGradient ramp the value from one to zero along the X axis
  • kNegYGradient ramp the value from one to zero along the Y axis
  • kNegZGradient ramp the value from one to zero along the Z axis
  • kCenterGradient ramps the value from one at the center to zero at the edges
Parameters:
[out]methodstorage for returning the method by which the fluid fuel values in the grid is determined
[out]gradientstorage for returning the gradient type, which is only relevant if the method is kGradient
Returns:
Status code
Status Codes:
MStatus setCoordinateMode ( MFnFluid::CoordinateMethod  method)

Set the modes by which the UVW coordinate values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may have the following values:

  • kFixed values are equal the object space coordinates
  • kGrid coordinate values will be moved using the current density solver
Parameters:
[in]methodmethod for determining the fluid UVW coordinates in the grid
Returns:
Status code
Status Codes:
MStatus getCoordinateMode ( MFnFluid::CoordinateMethod method)

Get the modes by which the UVW coordinates values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kFixed values are equal the object space coordinates
  • kGrid coordinate values will be moved using the current density solver
Parameters:
[out]methodstorage for returning the method by which the fluid coordinate values in the grid is determined
Returns:
Status code
Status Codes:
MStatus setColorMode ( MFnFluid::ColorMethod  method)

Set the modes by which the color values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may have the following values:

  • kZero the shaders color is used
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
Parameters:
[in]methodmethod for determining the fluid color in the grid
Returns:
Status code
Status Codes:
MStatus getColorMode ( MFnFluid::ColorMethod method)

Get the modes by which the color values in the grid are determined.

The values may be set by the user in various ways, or they may be computed as part of a simulation.

The method parameter may return the following values:

  • kZero the shaders color is used
  • kStaticGrid values in the grid are static
  • kDynamicGrid values in the grid come from a dynamic solver
Parameters:
[out]methodstorage for returning the method by which the fluid color in the grid is determined
Returns:
Status code
Status Codes:
MStatus getForceAtPoint ( const MPointArray point,
const MVectorArray velocity,
const MDoubleArray mass,
MVectorArray force,
double  deltaTime = 1.0 / 24.0 
)

Compute the force of the fluid as a field on an array of points, given their position, velocity, and mass.

This method uses MPointArray to represent the positions of points. If a point instance is in a rational form or a homogenous form, you should reset it to be in the cartesian form P(x, y, z, 1).

Parameters:
[in]pointarray of positions for each point.
[in]velocityarray of velocities for each point. If the length of the velocity array is 0, a velocity of 0.0 is assumed for all the points.
[in]massarray of mass values for each point. If the length of the mass array is 0, a mass of 1.0 is assumed for all the points.
[out]forceoutput array of forces applied to each point. If the length of the force array supplied is 0, the array is automatically resized. If the contents of the force array contains data, the computed force is added to the supplied data. This can be useful to accumulate forces of multiple fields.
[in]deltaTimetime increment in seconds. Default is (1.0 / 24.0 fps).
Returns:
Status code
Status Codes:
MStatus getForceAtPoint ( const MVectorArray point,
const MVectorArray velocity,
const MDoubleArray mass,
MVectorArray force,
double  deltaTime = 1.0 / 24.0 
)

Compute the force of a field on an array of points, given their position, velocity, and mass.

Note that only the Air and Vortex fields require a time increment to compute forces, all other fields will igonore this argument.

This method uses MVectorArray to represent the positions of a point.

Parameters:
[in]pointarray of positions for each point.
[in]velocityarray of velocities for each point. If the length of the velocity array is 0, a velocity of 0.0 is assumed for all the points. Note the velocity array is a requirement for the Air and Drag fields to compute forces.
[in]massarray of mass values for each point. If the length of the mass array is 0, a mass of 1.0 is assumed for all the points.
[out]forceoutput array of forces applied to each point. If the length of the force array supplied is 0, the array is automatically resized. If the contents of the force array contains data, the computed force is added to the supplied data. This can be useful to accumulate forces of multiple fields.
[in]deltaTimetime increment in seconds for usage with the Air and Vortex fields. Default is (1.0 / 24.0 fps).
Returns:
Status code
Status Codes:
bool toGridIndex ( const MPoint objectSpacePoint,
int3 &  gridCoords,
MStatus status = NULL 
)

For the given point in object space, get the grid indices of the voxel that it happens to lie in.

If the point is outside the fluid, the method returns false, and the indices should not be used.

Parameters:
[in]objectSpacePointan object space location
[out]gridCoordsthe voxel indices, if the point falls inside a voxel
[out]statusStatus code
Returns:
True if the point is inside the fluid, false otherwise
Status Codes:
Examples:
simpleFluidEmitter.cpp.
MStatus voxelCenterPosition ( int  xi,
int  yi,
int  zi,
MPoint objectSpacePoint 
)

For the given voxel, get the location of the center in object space.

If the voxel indices are not valid, the point may not be set to a valid point

Parameters:
[in]xithe voxel x index
[in]yithe voxel y index
[in]zithe voxel z index
[out]objectSpacePointthe object space location
Returns:
Status code
Status Codes:
  • MS::kSuccess The method was successful.
  • MS::kFailure The voxel index was out of range, or an object error has occurred.
MStatus updateGrid ( )

Tells the fluid shape that the contents of the fluid grid has changed.

It is necessary to call this routine after modifying internal fluid data via a pointer recieved from any of the access routines in this function set. Failure to call this will result in the fluid not drawing with your changes.

Returns:
Status code
Status Codes:
void emitIntoArrays ( float  val,
int  x,
int  y,
int  z,
float  density,
float  heat,
float  fuel,
bool  doColor,
const MColor emitColor 
)

Use this method to add density, heat, fuel, and/or color to a particular voxel of a fluid.

Parameters:
[in]valmultiplier applied to the specified density, heat, and fuel values.
[in]xvoxel index in x
[in]yvoxel index in y
[in]zvoxel index in z
[in]densityamount of density to add to the voxel
[in]heatamount of heat to add to the voxel
[in]fuelamount of fuel to add to the voxel
[in]doColorif true, then color specified by "emitColor" will be blended into the voxel's current color, with the blend coefficients being determined by the amount of density that is being added to the voxel.
[in]emitColorcolor to be blended into the voxel.
Examples:
simpleFluidEmitter.cpp.
int index ( int  xi,
int  yi 
)

This is a utility routine for finding the index of a cell in an array of fluid data.

The data in the fluid shape, such as color and density are passed back as single dimensional arrays of numeric values. This method converts three dimensional coordinates of a cell into the index value that refers the cell's value in the single dimensional array.

Note that no bounds checking is performed.

Parameters:
[in]xiindex in x
[in]yiindex in y
Returns:
Index in the single dimensional array
Examples:
simpleFluidEmitter.cpp.
int index ( int  xi,
int  yi,
int  zi 
)

This is a utility routine for finding the index of a cell in an array of fluid data.

The data in the fluid shape, such as color and density are passed back as single dimensional arrays of numeric values. This method converts three dimensional coordinates of a cell into the index value that refers the cell's value in the single dimensional array.

Note that no bounds checking is performed.

Parameters:
[in]xiindex in x
[in]yiindex in y
[in]ziindex in z
Returns:
Index in the single dimensional array
void index ( int  index,
int &  xi,
int &  yi,
int &  zi 
)

This is a utility routine for finding the coordinates of a cell in an array of fluid data given the index.

The data in the fluid shape, such as color and density are passed back as single dimensional arrays of numeric values. This method converts the index value that refers to a cell's value in the single dimensional array into the three dimensional coordinates of the cell.

Note that no bounds checking is performed.

Parameters:
[in]indexindex to convert into coordinates
[out]xistorage for the index in x
[out]yistorage for the index in y
[out]zistorage for the index in z
int index ( int  xi,
int  yi,
int  zi,
int  xres,
int  yres,
int  zres 
)

This is a utility routine for finding the index of a cell given the X, Y and Z resolutions.

This is intended for use primarily with the velocity arrays, where the resolutions are different for each array. The X velocity array is one bigger in X, etc.

This method converts three dimensional coordinates of a cell into the index value that refers the cell's value in the single dimensional array.

Note that no bounds checking is performed.

Parameters:
[in]xiindex in x
[in]yiindex in y
[in]ziindex in z
[in]xresresolution in x
[in]yresresolution in y
[in]zresresolution in z
Returns:
Index in the single dimensional array
void index ( int  index,
int  xres,
int  yres,
int  zres,
int &  xi,
int &  yi,
int &  zi 
)

This is a utility routine for finding the coordinates of a cell given the index, and the X, Y and Z resolutions.

This is intended for use primarily with the velocity arrays, where the resolutions are different for each array. The X velocity array is one bigger in X, etc.

This method converts the index value that refers to a cell's value in the single dimensional array into the three dimensional coordinates of the cell.

Note that no bounds checking is performed.

Parameters:
[in]indexindex to convert into coordinates
[in]xresresolution in x
[in]yresresolution in y
[in]zresresolution in z
[out]xistorage for the index in x
[out]yistorage for the index in y
[out]zistorage for the index in z

MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid
MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid MFnFluid