Trapping 101 - Reboot

Looking back at my post on the Portcullis - it blows.  I'm going to start over on the series.  But coherently this time.

The Thief class goes back to Supplement I - Greyhawk in 1976, with the ability to "Disarm Traps".  Note that it didn't address finding them, but it's assumed that you can find them if you can disarm them.  Now when it comes to DMing, I'm the type who needs to think out the descriptions in advance, I suck at making up details on the fly.  So the question I wanted to answer was - when the die roll says they found the trap, what have they actually found?

I doubt that it's a sign that says "TRAP".  Instead it must be something that indicates there's trap there.  They may have found the trap, i.e. the pit trap may be standing open; but it's more likely that what they've actually found is evidence of the trap.  A suspicious patch of floor or an oddly regular hole in the wall.  Or they may have found the trigger mechanism, a trip cord or lever or something.  Or the crushed skull and bones of the last victim.

 So what I did was list the physical evidence you might encounter for a particular type of trap;how it might be triggered and the evidence that the trigger would leave.  That becomes the result of the "Detect Trap" die roll.

In making the lists, I found a serendipitous bonus - many of the traps not only use the same trigger mechanisms, but also are physically similar, so that just describing what they've found does not necessarily let the party know what the trap is.

Analyzing the lists, I came to a few conclusions.  Traps can be categorized by effect, allowing me to weight what type of trap is there.

Channeling - Traps that prevent/require the characters to move along certain paths.  (Chutes, Portcullises)
Deadfalls - Traps that drop something
Pit traps - Holes that things fall into
Spells - Traps that involve magical effects
Weapons - Traps that swing a blade or club or fire a missile

 Reasonable trap and trigger combinations are dependent on the object trapped.  A door could have a pit trap or a poison needle associated with it.  A corridor could have a pit trap, but the poison needle trap doesn't make any sense in that location.

So for each type of object trapped I listed the possible triggers

Space
    Stepping on a lever
    Stepping on a trap
    Pulling a tripwire
    Reading a glyph
    Being observed (command activated)

Door
    Pulling a tripwire
    Reading a glyph
    Being observed (command activated)
    Opening
    Closing
    Passing through
    Locking
    Unlocking

Container
    Pulling a tripwire
    Reading a glyph
    Being observed (command activated)
    Opening
    Closing
    Locking
    Unlocking
    Moving

Now that I have all this information I can put together random tables to generate the trap, trigger and what the party observes when they find it.  That will be the subject of my next post on the subject.