Add possibility to rotate through custom rotation matrices about numpy-stl HOT 2 CLOSED

  def rotation(self, orient):
      "This function might cause xy-plane rotation, that does not matter much"
      alpha = 0.5 * math.pi - math.atan2(orient[Y], orient[X]) 
      beta = -0.5 * math.pi - math.atan2(
          orient[Z], math.sqrt(orient[X] ** 2 + orient[Y] ** 2))

      sin_a = math.sin(alpha)
      cos_a = math.cos(alpha)
      sin_b = math.sin(beta)
      cos_b = math.cos(beta)
      rotation_matrix = numpy.transpose((
          (cos_a, -sin_a, 0),
          (cos_b * sin_a, cos_b * cos_a, -sin_b),
          (sin_b * sin_a, sin_b * cos_a, cos_b),
      ))

      return rotation_matrix

def transform(self, orient):
      rotation_matrix = self.rotation(orient)

      rotated_vectors = numpy.dot(self.vectors, rotation_matrix)
      rotated_vectors = numpy.array(rotated_vectors, dtype='float32')
      max_ = rotated_vectors.max(axis=(0, 1))
      min_ = rotated_vectors.min(axis=(0, 1))
      rotated_vectors[:, :, Z] -= min_[Z] # translation to have Z_min == 0.  Not required per se
      max_[Z] -= min_[Z]
      min_[Z] -= min_[Z]

      return rotated_vectors, rotation_matrix