As we know, the resolution of 3DAP is anisotropic. The best resolution is reached along the needle axis direction, and could below 0.25 nm. However, the resolution along transverse direction is worse, and may around 1nm. Then, when we apply radial distribution function to analyze the atomic pairing relationship in 3DAP data, the result with 1nm is not reliable and may be wrong. I think this conclusion is true and what do you think. Is there any other reliable method to find the nano-sized cluster in a system. Thanks.