def createBrushMask(shape, style="Round", offset=(0, 0, 0), box=None, chance=100, hollow=False):
    """
    Return a boolean array for a brush with the given shape and style.
    If 'offset' and 'box' are given, then the brush is offset into the world
    and only the part of the world contained in box is returned as an array.
    :param shape, UNKWOWN
    :param style, style of the brush. Round if not given.
    :param offset, UNKWOWN
    :param box, UNKWOWN
    :param chance, also known as Noise. Input in stock-brushes like Fill and Replace.
    :param hollow, input to calculate a hollow brush.
    """

    #We are returning indices for a Blocks array, so swap axes
    if box is None:
        box = BoundingBox(offset, shape)
    if chance < 100 or hollow:
        box = box.expand(1)

    outputShape = box.size
    outputShape = (outputShape[0], outputShape[2], outputShape[1])

    shape = shape[0], shape[2], shape[1]
    offset = numpy.array(offset) - numpy.array(box.origin)
    offset = offset[[0, 2, 1]]

    inds = numpy.indices(outputShape, dtype=float)
    halfshape = numpy.array([(i >> 1) - ((i & 1 == 0) and 0.5 or 0) for i in shape])

    blockCenters = inds - halfshape[:, newaxis, newaxis, newaxis]
    blockCenters -= offset[:, newaxis, newaxis, newaxis]

    # odd diameter means measure from the center of the block at 0,0,0 to each block center
    # even diameter means measure from the 0,0,0 grid point to each block center

    # if diameter & 1 == 0: blockCenters += 0.5
    shape = numpy.array(shape, dtype='float32')

    # if not isSphere(shape):
    if style == "Round":
        blockCenters *= blockCenters
        shape /= 2
        shape *= shape

        blockCenters /= shape[:, newaxis, newaxis, newaxis]
        distances = sum(blockCenters, 0)
        mask = distances < 1
    elif style == "Cylinder":
        pass

    elif style == "Square":
        blockCenters /= shape[:, None, None, None]

        distances = numpy.absolute(blockCenters).max(0)
        mask = distances < .5

    elif style == "Diamond":
        blockCenters = numpy.abs(blockCenters)
        shape /= 2
        blockCenters /= shape[:, newaxis, newaxis, newaxis]
        distances = sum(blockCenters, 0)
        mask = distances < 1
    else:
        raise ValueError("Unknown style: " + style)

    if (chance < 100 or hollow) and max(shape) > 1:
        threshold = chance / 100.0
        exposedBlockMask = numpy.ones(shape=outputShape, dtype='bool')
        exposedBlockMask[:] = mask
        submask = mask[1:-1, 1:-1, 1:-1]
        exposedBlockSubMask = exposedBlockMask[1:-1, 1:-1, 1:-1]
        exposedBlockSubMask[:] = False

        for dim in (0, 1, 2):
            slices = [slice(1, -1), slice(1, -1), slice(1, -1)]
            slices[dim] = slice(None, -2)
            exposedBlockSubMask |= (submask & (mask[slices] != submask))
            slices[dim] = slice(2, None)
            exposedBlockSubMask |= (submask & (mask[slices] != submask))

        if hollow:
            mask[~exposedBlockMask] = False
        if chance < 100:
            rmask = numpy.random.random(mask.shape) < threshold

            mask[exposedBlockMask] = rmask[exposedBlockMask]

    if chance < 100 or hollow:
        return mask[1:-1, 1:-1, 1:-1]
    else:
        return mask

    Return a boolean array for a brush with the given shape and style.
    If 'offset' and 'box' are given, then the brush is offset into the world
    and only the part of the world contained in box is returned as an array.
    :param shape, UNKWOWN
    :param style, style of the brush. Round if not given.
    :param offset, UNKWOWN
    :param box, UNKWOWN
    :param chance, also known as Noise. Input in stock-brushes like Fill and Replace.
    :param hollow, input to calculate a hollow brush.
    
editortools/brush.py