Get nodes next to selected node (via sphere)

Hi,

in order to set up rigid elements automatically I am trying to find a node within a sphere from one selected node. I have no idea how this works, but I can see some Hw built in functions which have this kind of functionality. Unfortunately all I get from the command file is a node list, what is insufficient as I plan to do it mesh independant.

Can you help?

Thanks in advance,

Merula

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