public Operation build() {
        BlockTransformExtent extent = new BlockTransformExtent(clipboard, transform, targetWorldData.getBlockRegistry());
        ForwardExtentCopy copy = new ForwardExtentCopy(extent, clipboard.getRegion(), clipboard.getOrigin(), targetExtent, to);
        copy.setTransform(transform);
        if (ignoreAirBlocks) {
            copy.setSourceMask(new ExistingBlockMask(clipboard));
        }
        return copy;
    }