This is a short addendum to Ivan Solaris' article on "When do NPCs go away".

There are a couple of classes of monsters that were left off:  those that
appear or disappear on given days, as designated in the 'edit monster'
window for each particular monster.  Here's what I had happen in the
scenario I'm currently working on:

Gwen sells alchemy.  It's a small scenario, but high level, so I'd like her
to offer a lot of the recipes, just not all at once.  So I make three
Gwens: Gwen1 appears on days 1, 4, 7, etc., Gwen2 on days 2, 5, 8; Gwen3 on
3, 6, 9.  Each Gwen sells a different set of recipes.  Also, I have Dude1,
who sits in the inn and makes light conversation until day 6, when he
disappears.  Dude2 appears on day 6 and says Dude1 is a bad guy and he's
tracking him, have you seen him, etc.

New classes for the list:
10. Monsters set to appear on a given day or days
11. Monsters set to disappear on a given day or days

Conditions of change:
a. exit & reentry
b. exit & reset
(This particular town is all friendlies, so it won't ever be abandoned.)

Results:
10A appears as scheduled.
10B appears as scheduled.

11A DOESN'T disappear as scheduled.
11B disappears as scheduled.

In other words, you need the town to be reset for disappearing monsters to
do so.  Appearing monsters always appear if the day is right.

So I playtest my scenario, and discover, on day 2, TWO Gwens, Gwen1 and
Gwen2!  The new Gwen has appeared, but the old Gwen has not disappeared
because the town hasn't been reset.  I discover, on day 6, Dude1, sitting
in the inn, and Dude2, sitting NEXT TO HIM, saying "I'm looking for Dude1."
Same explanation.

Solution:
Completely scrap the idea of using "appear/disappear on day...".  Use Day
Reached?, Place Town Encounter, & Destroy Monster nodes in a chain upon
town entry.  Make 3 separate monster types, all identical, for townsperson
Gwen, so only the correct one would be destroyed.  Change Gwen's rotation
to Gwen1 on days 1-6, Gwen2 on days 7-12, Gwen three on days 12+.  These
changes worked, but took longer to implement and were more complicated than
the "appear/disappear on day..." functions would have been if they worked.

My scenario is small, so I can't count on the player travelling great
distances and visiting many towns before coming back.  In my opinion, the
way this works really cripples the "appear/disappear on day..." function. I
don't know if I'll ever use it, unless I'm making a really big scenario.

Scott Evans
mountaineer@loop.com

--Scott

"It's a man's life in the British Dental Association."
-Lemming of the BDA