Package com.openinventor.inventor

Class SbRotation

java.lang.Object
com.openinventor.inventor.SbBasic
com.openinventor.inventor.SbRotation
public class SbRotation extends SbBasic
Class for representing a rotation. Object that stores a rotation. There are several ways to specify a rotation: quaternion (4 floats, in the order x, y, z, w), 4x4 rotation matrix, or axis and angle. All angles are in radians and all rotations are right-handed.

The rotation value is stored internally as a quaternion. Quaternion representation is more compact, faster to compute and more numerically stable than rotation matrices. Quaternion representation allows smooth rotation (spherical linear interpolation) and avoids the problem of "gimbal lock" associated with Euler angles. It is not necessary to deal directly with quaternions. Many convenience methods are provided to set and get rotations using matrix and axis/angle representations.

Rotations are most commonly specified using an axis and an angle in radians. A common mistake is to use the constructor or setValue method that takes four float values, when intending to set an axis and angle. The methods that take four float values directly specify the quaternion value, which is probably not the intended result. For example: 

 // Create a rotation of PI/2 radians around the Z axis:
 
 // Incorrect.
 // (Compiles, but actually sets the quaternion value directly!)
 SbRotation rotation1 = new SbRotation(0, 0, 1, 1.5707963f);
 
 // This is the correct rotation.
 SbRotation rotation2 = new SbRotation(new SbVec3f(0, 0, 1), 1.5707963f);

See Also:

  • Field Details

    • array

      public final float[] array

  • Constructor Details

    • SbRotation

      public SbRotation(SbRotation copyFrom)

    • SbRotation

      public SbRotation(float[] components)

    • SbRotation

      public SbRotation(float q0, float q1, float q2, float q3)
      Constructor. The quaternion constructor takes four floats that define a quaternion.
      Note this is NOT the same as an axis/radian definition.

    • SbRotation

      public SbRotation()
      Default constructor. The initial value is no rotation.

    • SbRotation

      public SbRotation(SbMatrix m)
      Constructor. The matrix constructor takes a valid rotation matrix.

    • SbRotation

      public SbRotation(SbMatrix3 m)
      Constructor. The matrix constructor takes a valid 3x3 rotation matrix.

    • SbRotation

      public SbRotation(SbVec3f axis, float radians)
      Constructor. The axis/radians constructor creates a rotation of angle radians about the given axis.

    • SbRotation

      public SbRotation(SbVec3f rotateFrom, SbVec3f rotateTo)
      Constructor. The rotateFrom/To constructor defines a rotation that rotates from one vector into another. The rotateFrom and rotateTo vectors are normalized by the constructor before calculating the rotation.

  • Method Details

    • setValue

      public SbRotation setValue(float[] components)

    • getValue

      public float[] getValue()

    • setValue

      public SbRotation setValue(float[] components, int startIndex)

    • setValue

      public void setValue(SbRotation copyFrom)

    • scaleAngle

      public void scaleAngle(float scaleFactor)
      Keep the axis the same. Multiply the angle of rotation by the amount scaleFactor.

    • multVec

      public SbVec3f multVec(SbVec3f src)
      Multiplies the given vector by the matrix of this rotation.

    • times

      public SbRotation times(SbRotation q2)
      Multiplication of two rotations; results in product of rotations.

    • identity

      public static SbRotation identity()
      Returns a null rotation.

    • toArray

      public static SbRotation[] toArray(long nativeArray, long length)

    • setValue

      public SbRotation setValue(float q0, float q1, float q2, float q3)
      Sets value of rotation from 4 individual components of a quaternion.

    • slerp

      public static SbRotation slerp(SbRotation rot0, SbRotation rot1, float t)
      Spherical linear interpolation: as t goes from 0 to 1, returned value goes from rot0 to rot1.

    • getMatrix

      public SbMatrix getMatrix()
      Returns corresponding 4x4 rotation matrix.

    • setValue

      public SbRotation setValue(SbMatrix3 m)
      Sets rotation from a 3x3 rotation matrix.

    • decompose

      public SbRotation.AxisAngle decompose()
      Returns corresponding 3D rotation axis vector and angle in radians.

    • setValue

      public SbRotation setValue(SbVec3f axis, float radians)
      Sets value of vector from 3D rotation axis vector and angle in radians.

    • getMatrix3

      public SbMatrix3 getMatrix3()
      Returns corresponding 3x3 rotation matrix.

    • invert

      public SbRotation invert()
      Changes a rotation to be its inverse.

    • inverse

      public SbRotation inverse()
      Returns the inverse of a rotation.

    • setValue

      public SbRotation setValue(SbMatrix m)
      Sets value of rotation from a rotation matrix.

    • getMatrixd

      public SbMatrixd getMatrixd()
      Returns corresponding 4x4 rotation matrix.

    • setValue

      public SbRotation setValue(SbVec3f rotateFrom, SbVec3f rotateTo)
      Sets rotation to rotate one direction vector to another. The rotateFrom and rotateTo arguments are normalized before the rotation is calculated.

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • equals

      public boolean equals(SbRotation r, float tolerance)
      Equality comparison within given tolerance - the square of the length of the maximum distance between the two quaternion vectors.

    • setValue

      public SbRotation setValue(SbMatrixd md)
      Sets rotation from a double precision rotation matrix.

    • setValue

      public SbRotation setValue(SbRotationd rotated)
      Sets rotation from a double precision rotation.

    • multiply

      public void multiply(SbRotation q)
      Multiplies by another rotation; results in product of rotations.