This is kinda a mix of question, feedback and possible bug report. I've already posted this in the general forum (
https://7daystodie.com/forums/showthread.php?134748-In-Search-of-a-Random-Blood-Moon), but I feel I might have more responsiveness here. My apologies for the double-post.
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NOTE: This is specifically for MP RWG; I haven't played SP in several versions.
The idea of a Blood Moon every 7 days has always been a bit formulaic to me, and I've been in search of a way to get a true random Blood Moon. A17 provided an answer to this in the Blood Moon Frequency/Range, but if I'm not mistaken, something has changed in the way that's calculated slightly in A18. Am not sure if I'm (a) derping and not remembering right [it's quite possible], or (b) something actually changed.
Regardless of that answer, the way that it appears to be handled in A18 is a bit counter-intuitive and "spoiler-ish" to me.
In A17, I used to run a frequency of 1 with a range of 5, which basically gave me a 20% chance per day, where one Blood Moon must occur every 5 days at minimum. Back to backs, were possible, but of course with a diminishing chance. For instance, the first BM happened between 2-6 days away. This is the way I'd expect it work: 1 + RND(5)
Now, in A18, it appears now that the Frequency determines the first day of the Blood Moon, regardless of the Range. For instance, a 1/5, as before will happen on day 1 *always*, then proceed as normal. A 2/5, the first blood *always* happens on Day 2, then proceeds as normal. More like FRQ+RND(5)
I've tested this on two RWG maps with about 25 fresh starts of the server: keeping the Generated Worlds folder and deleting the profiles file along with the actual generated county folder, and then checking the log for the BM days. Each time, the Blood Moon always, without fail, starts on the Frequency day. The NEXT BM varies as I would expect, but that first BM always seems to land on the Frequency.
This seems a bit counter-intuitive, and spoiler-ish, considering using this, you can pick the day the Blood Moon begins on.