def METHOD_NAME(self, random_generator, indices, which_seed):
    """
    Generate the next seed position (Space=voxmm, origin=corner).
    Parameters
    ----------
    random_generator : numpy random generator
        Initialized numpy number generator.
    indices : List
        Indices of current seeding map.
    which_seed : int
        Seed number to be processed.
    Return
    ------
    seed_pos: tuple
        Position of next seed expressed in mm.
    """
    len_seeds = len(self.seeds_vox)
    if len_seeds == 0:
        return []
    # Voxel selection from the seeding mask
    ind = which_seed % len_seeds
    x, y, z = self.seeds_vox[indices[ind]]
    # Subvoxel initial positioning. Right now x, y, z are in vox space,
    # origin=corner, so between 0 and 1.
    r_x = random_generator.uniform(0, 1)
    r_y = random_generator.uniform(0, 1)
    r_z = random_generator.uniform(0, 1)
    # Moving inside the voxel
    x += r_x
    y += r_y
    z += r_z
    if self.origin == Origin('center'):
        # Bound [0, 0, 0] is now [-0.5, -0.5, -0.5]
        x -= 0.5
        y -= 0.5
        z -= 0.5
    if self.space == Space.VOX:
        return x, y, z
    elif self.space == Space.VOXMM:
        return x * self.voxres[0], y * self.voxres[1], z * self.voxres[2]
    else:
        raise NotImplementedError("We do not support rasmm space.")