... now with 35% more arrogance!

Saturday, July 23, 2011

Ultimate Infravision

On Dragonsfoot, someone asked whether characters with infravision and no light source would be able to see undead creatures. The usual discussion ensued: whether infravision detects creatures or objects that radiate more (or less) heat than their surroundings, or whether the tiny differences in ambient heat is enough.

M response was so perfect and solves the problem once and for all*, so I thought I'd repost it here:
Suppose there is no light source, just infravision, and no undead. Do the adventurers run into walls?

If yes: they can't see undead, either.

If not: they can see the undead.
You don't really need to get more technical than that. I do, however, think I would halve the encounter distances for wandering undead, just on the grounds that they stand out less from their surroundings.

* Yeah, right.


  1. Elegant solution. I do find it humorous, though, that people can get so upset discussing points about

    1) a game made up by a bunch of nerds in Lake Geneva in the 70s and

    2) the 'reality' of a shared fantasy world.

    It's true that people's minds disengage when they discuss something they're emotionally involved in, so you're disclaimer about the likelihood of 'solving' the dilemma is on the money.

  2. I always assumed it worked like infra-red goggles, you can still see, even without a light source, because the light source is the heat radiated by nearby objects. Colder objects are dimmer, but still visible, if a bit shadowy. So, undead would be a shadowy figure moving through a shadowy environment, but the you could still see the movement.

  3. @DaveL: when I care about the "rationale", that's my interpretation, too. Basically, I think of it as a way to see gross structural details and moving objects, with the special effect of warm-blooded creatures showing up like candles. Cold-blooded and undead creatures would not be identifiable, but they'd be visible as shadows. If a wizard were to research the Invisible Heat Globe spell, that would act as Light/Continual Light, allowing creatures with infravision to see details and possibly do things like read,