Section: Visualization Toolkit Rendering Classes
To use this class, specify at least two pairs of (t,q[4]) with the AddQuaternion() method. Next interpolate the tuples with the InterpolateQuaternion(t,q[4]) method, where "t" must be in the range of (t_min,t_max) parameter values specified by the AddQuaternion() method (t is clamped otherwise), and q[4] is filled in by the method.
There are several important background references. Ken Shoemake described the practical application of quaternions for the interpolation of rotation (K. Shoemake, "Animating rotation with quaternion curves", Computer Graphics (Siggraph '85) 19(3):245--254, 1985). Another fine reference (available on-line) is E. B. Dam, M. Koch, and M. Lillholm, Technical Report DIKU-TR-98/5, Dept. of Computer Science, University of Copenhagen, Denmark.
To create an instance of class vtkQuaternionInterpolator, simply invoke its constructor as follows
obj = vtkQuaternionInterpolator
obj
is an instance of the vtkQuaternionInterpolator class.
string = obj.GetClassName ()
int = obj.IsA (string name)
vtkQuaternionInterpolator = obj.NewInstance ()
vtkQuaternionInterpolator = obj.SafeDownCast (vtkObject o)
int = obj.GetNumberOfQuaternions ()
- Return the number of quaternions in the list of quaternions to be
interpolated.
double = obj.GetMinimumT ()
- Obtain some information about the interpolation range. The numbers
returned (corresponding to parameter t, usually thought of as time)
are undefined if the list of transforms is empty. This is a convenience
method for interpolation.
double = obj.GetMaximumT ()
- Obtain some information about the interpolation range. The numbers
returned (corresponding to parameter t, usually thought of as time)
are undefined if the list of transforms is empty. This is a convenience
method for interpolation.
obj.Initialize ()
- Reset the class so that it contains no data; i.e., the array of (t,q[4])
information is discarded.
obj.AddQuaternion (double t, double q[4])
- Add another quaternion to the list of quaternions to be interpolated.
Note that using the same time t value more than once replaces the
previous quaternion at t. At least one quaternions must be added to
define an interpolation functios.
obj.RemoveQuaternion (double t)
- Delete the quaternion at a particular parameter t. If there is no
quaternion tuple defined at t, then the method does nothing.
obj.InterpolateQuaternion (double t, double q[4])
- Interpolate the list of quaternions and determine a new quaternion
(i.e., fill in the quaternion provided). If t is outside the range of
(min,max) values, then t is clamped to lie within the range.
obj.SetInterpolationType (int )
- Specify which type of function to use for interpolation. By default
(SetInterpolationFunctionToSpline()), cubic spline interpolation using a
modifed Kochanek basis is employed. Otherwise, if
SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation
is used between each pair of quaternions.
int = obj.GetInterpolationTypeMinValue ()
- Specify which type of function to use for interpolation. By default
(SetInterpolationFunctionToSpline()), cubic spline interpolation using a
modifed Kochanek basis is employed. Otherwise, if
SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation
is used between each pair of quaternions.
int = obj.GetInterpolationTypeMaxValue ()
- Specify which type of function to use for interpolation. By default
(SetInterpolationFunctionToSpline()), cubic spline interpolation using a
modifed Kochanek basis is employed. Otherwise, if
SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation
is used between each pair of quaternions.
int = obj.GetInterpolationType ()
- Specify which type of function to use for interpolation. By default
(SetInterpolationFunctionToSpline()), cubic spline interpolation using a
modifed Kochanek basis is employed. Otherwise, if
SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation
is used between each pair of quaternions.
obj.SetInterpolationTypeToLinear ()
- Specify which type of function to use for interpolation. By default
(SetInterpolationFunctionToSpline()), cubic spline interpolation using a
modifed Kochanek basis is employed. Otherwise, if
SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation
is used between each pair of quaternions.
obj.SetInterpolationTypeToSpline ()