MFnField Class Reference
[OpenMayaFX - API module for effects]

#include <MFnField.h>
Inheritance diagram for MFnField:
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List of all members.

Detailed Description

Function set for Dynamic Fields.

Function set for creation, edit, and query of Dynamic Fields.

There are several types of dynamic fields: Air, Drag, Gravity, Newton Radial, Turbulence, Uniform, and Vortex.


Public Member Functions
virtual MFn::Type  type () const
  Function set type.
virtual  ~MFnField ()
  Destructor.
  MFnField ()
  Default constructor.
  MFnField (MObject &object, MStatus *ReturnStatus=NULL)
  Constructor.
  MFnField (const MDagPath &object, MStatus *ret=NULL)
  Constructor.
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)
double  magnitude (MStatus *ReturnStatus=NULL) const
MStatus  setMagnitude (double mag)
double  attenuation (MStatus *ReturnStatus=NULL) const
MStatus  setAttenuation (double atten)
double  maxDistance (MStatus *ReturnStatus=NULL) const
MStatus  setMaxDistance (double maxDist)
bool  perVertex (MStatus *ReturnStatus=NULL) const
MStatus  setPerVertex (bool enable)
bool  useMaxDistance (MStatus *ReturnStatus=NULL) const
MStatus  setUseMaxDistance (bool enable)
double  falloffCurve (const double param, MStatus *ReturnStatus=NULL)
bool  isFalloffCurveConstantOne (MStatus *ReturnStatus=NULL)
  MFnField (const MObject &object, MStatus *ret=NULL)
  Constructor.

Protected Member Functions
virtual const char *  className () const
  Class name.

Constructor & Destructor Documentation

MFnField::~MFnField (  )  [virtual]

Destructor.

Class destructor.

MFnField::MFnField ( 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:

MFnField::MFnField ( 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:

MFnField::MFnField ( 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:

Member Function Documentation

MFn::Type MFnField::type (  )  const [virtual]

Function set type.

Return the class type : MFn::kField

Reimplemented from MFnDagNode.

Reimplemented in MFnAirField, MFnDragField, MFnGravityField, MFnNewtonField, MFnRadialField, MFnTurbulenceField, MFnUniformField, MFnVolumeAxisField, and MFnVortexField.

MStatus MFnField::getForceAtPoint ( const MPointArray &  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 ignore this argument.

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. 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:

MStatus MFnField::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:

double MFnField::magnitude ( MStatus *  ReturnStatus = NULL  )  const

Returns the strength of the field.

Parameters:
[out]  ReturnStatus  Status code
Returns:
A value representing the strength of the field.
Status Codes:

MStatus MFnField::setMagnitude ( double  mag  ) 

Sets the strength of the field.

Parameters:
[in]  mag  A value representing the strength of the field.
Returns:
Status code
Status Codes:

double MFnField::attenuation ( MStatus *  ReturnStatus = NULL  )  const

Returns the rate of change where the strength of the field changes as the distance between the field and the affected object increases.

Parameters:
[out]  ReturnStatus  Status code
Returns:
  • A positive value representing the exponent for rate of change.
  • A value of 0 and the force remains constant over distance.
Status Codes:

MStatus MFnField::setAttenuation ( double  atten  ) 

Sets the rate of change where the strength of the field changes as the distance between the field and the affected object increases.

Parameters:
[in]  atten  A positive value representing the exponent for rate of change. A value of 0 and the force remains constant over distance.
Returns:
Status code
Status Codes:

double MFnField::maxDistance ( MStatus *  ReturnStatus = NULL  )  const

Returns the maximum distance from the field at which the force of the field is exerted. The Use Max Distance setting must be turned on for maximum distance to take effect. The maximum distance is scaled by the falloff curve's non-zero range.

Parameters:
[out]  ReturnStatus  Status code
Returns:
A value representing distance in internal linear units.
Status Codes:

MStatus MFnField::setMaxDistance ( double  dist  ) 

Sets the maximum distance from the field at which the force of the field is exerted. The Use Max Distance setting must be turned on for maximum distance to take effect.

Parameters:
[in]  dist  A value representing distance in internal linear units.
Returns:
Status code
Status Codes:

bool MFnField::perVertex ( MStatus *  ReturnStatus = NULL  )  const

Returns true if the field exerts its force on each individual point (cv, particle, vertex) equally. Returns false if the force is exerted only from the geometric center of the object or set of points.

Parameters:
[out]  ReturnStatus  Status code
Returns:
  • true Force is applied to each individual point.
  • false Force is applied from the geometric center.
Status Codes:

MStatus MFnField::setPerVertex ( bool  enable  ) 

Enables the field to exert its force on each individual point (cv, particle, vertex) equally. Otherwise, the force is exerted only from the geometric center of the object or set of points.

Parameters:
[in]  enable  Flag to enable or disable individual point forces.
Returns:
Status code
Status Codes:

bool MFnField::useMaxDistance ( MStatus *  ReturnStatus = NULL  )  const

Returns true if the field will use the maximum distance setting to determine the area of influence.

Parameters:
[out]  ReturnStatus  Status code
Returns:
  • true Field uses the maximum distance setting.
  • false Field ignores the maximum distance setting.
Status Codes:

MStatus MFnField::setUseMaxDistance ( bool  enable  ) 

Enables the field to use the maximum distance setting to determine the area of influence.

Parameters:
[in]  enable  Flag to enable or disable maximum distance.
Returns:
Status code
Status Codes:

double MFnField::falloffCurve ( const double  param,
MStatus *  ReturnStatus = NULL  
)

Returns falloff given the param in [0,1]. This is enabled if the use the maximum distance is enabled.

Parameters:
[in]  param  Parameter
[out]  ReturnStatus  Status code
Returns:
The falloff value given the param.
Status Codes:

bool MFnField::isFalloffCurveConstantOne ( MStatus *  ReturnStatus = NULL  ) 

Returns true if falloffCurve is a constant one (default) or false if not.

Parameters:
[out]  ReturnStatus  Status code
Returns:
If falloff curve always returns a constant one
Status Codes:
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