def set_motion_data(bvh_tree, data):
    """Sets the frames of bvh structure to values in data.
    
    :param bvh_tree: BVH structure.
    :type bvh_tree: bvhtree.BvhTree
    :param data: 2d array of float values. rows are frames, columns are channels.
    :type data: numpy.ndarray
    """
    bvh_tree.frames = data.astype(str).tolist()
