Discover physical network topology

I have three managed switches connected via stack interface modules. They have SNMP enabled. I can see them in DUDE and snmpwalk them no problem. Since they’re switches, they “know” what devices are connected to which ports so that they “know” where to send packets, right?

So my question is, how do I get the DUDE to use that “knowledge” to lay out the link structure properly on my network map?