MFnFluid Class Reference
[OpenMayaFX - API module for effects, FunctionSet classes]

#include <MFnFluid.h>

Inheritance diagram for MFnFluid:

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Collaboration diagram for MFnFluid:

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List of all members.

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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.

Public Types
enum	FluidMethod { kZero, kStaticGrid, kDynamicGrid, kGradient }
	Defines how voxel values are computed for most types of fluid data. More...
enum	FluidGradient {   kConstant, kXGradient, kYGradient, kZGradient,   kNegXGradient, kNegYGradient, kNegZGradient, kCenterGradient }
	Defines the orientation of the gradient. More...
enum	FalloffMethod { kNoFalloffGrid, kStaticFalloffGrid }
	Falloff data only supports a subset of the available fluid methods. More...
enum	ColorMethod { kUseShadingColor, kStaticColorGrid, kDynamicColorGrid }
	Color data has its own set of methods for computing voxel data. More...
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)
MObject	create2D (unsigned int Xres, unsigned int Yres, double Xdim, double Ydim, MObject parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
MStatus	getResolution (unsigned int &Xres, unsigned int &Yres, unsigned int &Zres) const
MStatus	getResolution (unsigned int &Xres, unsigned int &Yres) const
MStatus	getDimensions (double &Xdim, double &Ydim, double &Zdim) const
MStatus	setSize (unsigned int Xres, unsigned int Yres, unsigned int Zres, double Xdim, double Ydim, double Zdim, bool resample)
MStatus	setSize (unsigned int Xres, unsigned int Yres, double Xdim, double Ydim, bool resample)
unsigned int	gridSize (MStatus *ReturnStatus=NULL)
MStatus	velocityGridSizes (int &xsize, int &ysize, int &zsize)
float *	falloff (MStatus *ReturnStatus=NULL)
float *	density (MStatus *ReturnStatus=NULL)
MStatus	getVelocity (float *&Xvel, float *&Yvel, float *&Zvel)
float *	pressure (MStatus *ReturnStatus=NULL)
float *	temperature (MStatus *ReturnStatus=NULL)
float *	fuel (MStatus *ReturnStatus=NULL)
MStatus	getCoordinates (float *&u, float *&v, float *&w)
MStatus	getColors (float *&r, float *&g, float *&b)
MStatus	setFalloffMode (FalloffMethod mode)
MStatus	getFalloffMode (FalloffMethod &mode)
MStatus	setDensityMode (FluidMethod mode, FluidGradient gradient)
MStatus	getDensityMode (FluidMethod &mode, FluidGradient &gradient)
MStatus	setVelocityMode (FluidMethod mode, FluidGradient gradient)
MStatus	getVelocityMode (FluidMethod &mode, FluidGradient &gradient)
MStatus	setTemperatureMode (FluidMethod mode, FluidGradient gradient)
MStatus	getTemperatureMode (FluidMethod &mode, FluidGradient &gradient)
MStatus	setFuelMode (FluidMethod mode, FluidGradient gradient)
MStatus	getFuelMode (FluidMethod &mode, FluidGradient &gradient)
MStatus	setCoordinateMode (CoordinateMethod mode)
MStatus	getCoordinateMode (CoordinateMethod &mode)
MStatus	setColorMode (ColorMethod mode)
MStatus	getColorMode (ColorMethod &mode)
MStatus	getForceAtPoint (const MPointArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime=1.0/24.0)
MStatus	getForceAtPoint (const MVectorArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime=1.0/24.0)
bool	toGridIndex (const MPoint &objectSpacePoint, int3 &gridCoords, MStatus *status=NULL)
MStatus	voxelCenterPosition (int xi, int yi, int zi, MPoint &objectSpacePoint)
MStatus	updateGrid ()
void	emitIntoArrays (float val, int x, int y, int z, float density, float heat, float fuel, bool doColor, const MColor &emitColor)
int	index (int xi, int yi)
int	index (int xi, int yi, int zi)
void	index (int ai, int &xi, int &yi, int &zi)
int	index (int xi, int yi, int zi, int xres, int yres, int zres)
void	index (int ai, int xres, int yres, int zres, int &xi, int &yi, int &zi)
	MFnFluid (const MObject &object, MStatus *ret=NULL)
	Constructor.
Protected Member Functions
virtual const char *	className () const
	Class name.

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Member Enumeration Documentation

enum MFnFluid::FluidMethod

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.

enum MFnFluid::FluidGradient

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.

enum MFnFluid::FalloffMethod

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.

enum MFnFluid::ColorMethod

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.

enum MFnFluid::CoordinateMethod

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.

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Constructor & Destructor Documentation

MFnFluid::~MFnFluid

(

)

[virtual]

Destructor.

Destructor.

MFnFluid::MFnFluid	(	MObject &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

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

Parameters:

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

MFnFluid::MFnFluid	(	const MDagPath &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

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

Parameters:

[in]	object	The const MDagPath to attach the function set to
[out]	ReturnStatus	The return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

MFnFluid::MFnFluid	(	const MObject &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

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

Parameters:

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

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Member Function Documentation

MFn::Type MFnFluid::type

(

)

const [virtual]

Function set type.

Return the class type : MFn::kFluid

Reimplemented from MFnDagNode.

const char * MFnFluid::className

(

)

const [protected, virtual]

Class name.

Return the class name : "MFnFluid"

Reimplemented from MFnDagNode.

MObject MFnFluid::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]	Xres	number of fluid grid cells in the x dimension
[in]	Yres	number of fluid grid cells in the y dimension
[in]	Zres	number of fluid grid cells in the z dimension
[in]	Xdim	object space size in the x dimension
[in]	Ydim	object space size in the y dimension
[in]	Zdim	object space size in the z dimension
[in]	parent	specifies 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]	ReturnStatus	Status 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 MFnFluid::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]	Xres	number of fluid grid cells in the x dimension
[in]	Yres	number of fluid grid cells in the y dimension
[in]	Xdim	object space size in the x dimension
[in]	Ydim	object space size in the y dimension
[in]	parent	specifies 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]	ReturnStatus	Status 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 MFnFluid::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]	Xres	storage for returning the number of fluid grid cells in the x dimension
[out]	Yres	storage for returning the number of fluid grid cells in the y dimension
[out]	Zres	storage for returning the number of fluid grid cells in the z dimension

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

simpleFluidEmitter.cpp.

MStatus MFnFluid::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]	Xres	storage for returning the number of fluid grid cells in the x dimension
[out]	Yres	storage for returning the number of fluid grid cells in the y dimension

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	Xdim	storage for returning the dimension of the fluid in x
[out]	Ydim	storage for returning the dimension of the fluid in y
[out]	Zdim	storage for returning the dimension of the fluid in z

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

simpleFluidEmitter.cpp.

MStatus MFnFluid::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]	Xres	number of fluid grid cells in the x dimension
[in]	Yres	number of fluid grid cells in the y dimension
[in]	Zres	number of fluid grid cells in the z dimension
[in]	Xdim	object space size in the x dimension
[in]	Ydim	object space size in the y dimension
[in]	Zdim	object space size in the z dimension
[in]	resample	true 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 MFnFluid::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]	Xres	number of fluid grid cells in the x dimension
[in]	Yres	number of fluid grid cells in the y dimension
[in]	Xdim	object space size in the x dimension
[in]	Ydim	object space size in the y dimension
[in]	resample	true 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 MFnFluid::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]

ReturnStatus

Status code.

Returns:

The number of elements.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	xsize	storage for the x velocity grid size
[out]	ysize	storage for the y velocity grid size
[out]	zsize	storage for the z velocity grid size

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.

float * MFnFluid::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]

ReturnStatus

Status 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 * MFnFluid::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]

ReturnStatus

Status 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 MFnFluid::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]	Xvel	storage for returning a pointer to the x components of the velocity values in the grid
[out]	Yvel	storage for returning a pointer to the y components of the velocity values in the grid
[out]	Zvel	storage 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 * MFnFluid::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]

ReturnStatus

Status 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 * MFnFluid::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]

ReturnStatus

Status 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 * MFnFluid::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]

ReturnStatus

Status 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 MFnFluid::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]	u	storage for returning a pointer to the u values in the grid
[out]	v	storage for returning a pointer to the v values in the grid
[out]	w	storage for returning a pointer to the w values in the grid

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	r	storage for returning a pointer to the red components of the color values in the grid
[out]	g	storage for returning a pointer to the green components of the color values in the grid
[out]	b	storage 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 MFnFluid::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]

method

method for determining the falloff value in the grid

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]

method

storage for returning the method by which the falloff value in the grid is determined

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	method for determining the fluid density in the grid
[in]	gradient	gradient type, only used if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	storage for returning the method by which the fluid density in the grid is determined
[out]	gradient	storage for returning the gradient type, which is only relevant if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	method for determining the fluid velocity in the grid
[in]	gradient	gradient type, only used if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	storage for returning the method by which the fluid velocity in the grid is determined
[out]	gradient	storage for returning the gradient type, which is only relevant if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	method for determining the fluid temperature in the grid
[in]	gradient	gradient type, only used if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	storage for returning the method by which the fluid temperature in the grid is determined
[out]	gradient	storage for returning the gradient type, which is only relevant if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	method for determining the fluid fuel in the grid
[in]	gradient	gradient type, only used if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	method	storage for returning the method by which the fluid fuel values in the grid is determined
[out]	gradient	storage for returning the gradient type, which is only relevant if the method is kGradient

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]

method

method for determining the fluid UVW coordinates in the grid

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]

method

storage for returning the method by which the fluid coordinate values in the grid is determined

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]

method

method for determining the fluid color in the grid

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter An enum value that was passed in is invalid
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]

method

storage for returning the method by which the fluid color in the grid is determined

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	point	array of positions for each point.
[in]	velocity	array 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]	mass	array 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]	force	output 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]	deltaTime	time increment in seconds. Default is (1.0 / 24.0 fps).

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus MFnFluid::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]	point	array of positions for each point.
[in]	velocity	array 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]	mass	array 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]	force	output 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]	deltaTime	time increment in seconds for usage with the Air and Vortex fields. Default is (1.0 / 24.0 fps).

Returns:

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

bool MFnFluid::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]	objectSpacePoint	an object space location
[out]	gridCoords	the voxel indices, if the point falls inside a voxel
[out]	status	Status code

Returns:

True if the point is inside the fluid, false otherwise

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

simpleFluidEmitter.cpp.

MStatus MFnFluid::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]	xi	the voxel x index
[in]	yi	the voxel y index
[in]	zi	the voxel z index
[out]	objectSpacePoint	the 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 MFnFluid::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:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

void MFnFluid::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]	val	multiplier applied to the specified density, heat, and fuel values.
[in]	x	voxel index in x
[in]	y	voxel index in y
[in]	z	voxel index in z
[in]	density	amount of density to add to the voxel
[in]	heat	amount of heat to add to the voxel
[in]	fuel	amount of fuel to add to the voxel
[in]	doColor	if 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]	emitColor	color to be blended into the voxel.

Examples:

simpleFluidEmitter.cpp.

int MFnFluid::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]	xi	index in x
[in]	yi	index in y

Returns:

Index in the single dimensional array

Examples:

simpleFluidEmitter.cpp.

int MFnFluid::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]	xi	index in x
[in]	yi	index in y
[in]	zi	index in z

Returns:

Index in the single dimensional array

void MFnFluid::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]	index	index to convert into coordinates
[out]	xi	storage for the index in x
[out]	yi	storage for the index in y
[out]	zi	storage for the index in z

int MFnFluid::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]	xi	index in x
[in]	yi	index in y
[in]	zi	index in z
[in]	xres	resolution in x
[in]	yres	resolution in y
[in]	zres	resolution in z

Returns:

Index in the single dimensional array

void MFnFluid::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]	index	index to convert into coordinates
[in]	xres	resolution in x
[in]	yres	resolution in y
[in]	zres	resolution in z
[out]	xi	storage for the index in x
[out]	yi	storage for the index in y
[out]	zi	storage for the index in z