Darkvision: a thesis

[Nonlethal Force]

I love Chieromancer's explanation, that is cool. It might not be true to science, but then again neither is magic! As an explanation existing in a fantastical world, I like it. May I borrow it?

As to the glowing red eyes if the creature radiated their own darkvision, what about allowing the ability to be supressible as a free action. Thus, if the person/creature was underground and wanted to see with their darkvision they would show up as glowing red eyes, yet a creature who didn't want to show up could opt to suppress their darkvision and have normal sight - effectively ending their darkvision and making them just as blind as a normal human in the dark.

 

[Anguish]

Unfortunately, there's a problem with the R-light idea. Drow A has darkvision 120ft. Drow B has darkvision 120ft. The two Drow are 100ft from one another, but Drow A is hiding from unsuspecting Drow B. Drow A is watching from behind a rock as his prey approaches. Mysteriously Drow B doesn't say "hey, weird, there's a source of R-light behind that rock, illuminating everything within 120ft of it... must be another Drow, trying to hide from me".

Anything sonar-based where the sensor also emits any form of detectable particle doesn't work. Darkvision as it exists in 3rd edition has to work based on passive detection of something that's already present.

Now. If all objects bar none were constantly emitting R-light, then this could be a possibility. Drow A's emissions could be drowned out by the ambient R-lighting provided by the rock, the cavern walls, and the Cleric of Lloth sneaking up on HIM because Drow B is just a decoy.

Still, darkvision doesn't include shadows, does it? Oh-oh. Means this magical R-light stuff passes through things. So... Drow have neutrino detectors in their heads. But... if it's neutrinos, sadly... those would pass right through the rock Drow A is using for cover, revealing him utterly.

So... darkvision is darkvision. The end.

 

[Cheiromancer]

I love Cheiromancer's explanation, that is cool. It might not be true to science, but then again neither is magic! As an explanation existing in a fantastical world, I like it. May I borrow it?

Years ago I and my room-mate were co-DMs. We were playing in the Forgotten realms, but had slightly different opinions on everything from monster ecology to religion. In game this was handled by two feuding sages, Rolheiser and Jimmeister, who acted as our mouth-pieces. It worked great.

You may certainly use this explanation, but I think it would work best as the learned opinion of an out-of-the-way sage. (I was the second sage- some variant of Cheiro or Cheiromancer would also work.)

If a creature's darkvision is visible as "glowing red eyes" I'd think it should only be when you actually lock gazes with the creature, and only work within the range of the darkvision. Which means that if you can see it, it can definitely see you. Creatures with improved dark-vision might have different colored eyes, too.

 

[Lonely Tylenol]

Yeah, that's exactly how infravision was described in 1E. Every underground-dwelling creature would be seen as glowing red eyes when viewed by other infravision. Personally, I thought that was very cool and scary.

Perhaps, but in order to actually be able to see your glowing eyes would need to have the same luminous intensity as a flashlight. In order to be able to see as well as if you were in full illumination (which is how darkvision works), your eyes would need to be even brighter. You'd blind everyone else with infravision, and since the source is your eyes, probably yourself.

edit: for the sake of my example above, I assumed that the eyes were not the source of the radiation if it were emitted by the darkvision user, because that would cause its own problems. I figure a special organ in the forehead is sufficient.

That was only the case around 2E, when designers made a concerted attempt to complicate things. In 1E the mechanics were trivial.

In 1E the mechanics were identical. Infravision has always been infra-red vision, with everything that implies. I remember the infravision debates from back in my 1E days. The solution then, as well as now, is to avoid any mention of the mechanics of how the vision actually works and just say "you can see in the dark."