Difference between Ultraviolet Perception and Nightvision?

[Dust Raven]

Re: Difference between Ultraviolet Perception and Nightvision?

 

No, that's not what you said. I'll quote you again: "CN can see in total darkness while Supervision-Man can't." This is the problem: If nightvision is bought as +4 vision, with the limitation only vs darkness penalties, then someone who buys straight +4 vision has the same PER roll in the limited circumstance. In the example, both guys have 11- sight PER in darkness. The same thing as would happen if Ocean Man buys +4 Vision, Only underwater. He and Supervision-Man, have exactly the same vision under water. OM and CN's vision bonuses apply only in a limited circumstance, which SVM's applies all the time.

 

There is nothing in the rules (that I've seen) that says that a normal vision guy can't make a PER roll at -4 in total darkness. And if you rule that normal vision is outright impossible, i.e., no roll allowed at all, there is nothing in the construct of nightvision that allows for an exception. It's just a bonus to sight with a circumstance limitation.

 

My claim is that total darkness (or even almost total darkness) goes beyond simply -X to sight PER. And along with that, darkvision needs to be built as something beyond simply a +X to sight PER, with the "Only vs. darkness" limitation.

 

 

What about a character who has +4 Sight Perception, *without* the nightvision *limitation*? According to the rules, he should be able to see just as well in darkness, "total darkness," "pitch black," etc., as someone with Nightvision. Taking a limitation should not grant an advantage.

 

 

I may have not understood what you meant by this point. Contrast is required to distinguish the outlines of objects, too, not just their colors. Contrast in not just to allow you to distinguish the red stripe from the white stripe on a flag, it also allows you to distinguish the edge of the flag itself from the background.

 

 

So Nightvision would be useless as well. That's fine. So what power would you use to allow someone to see in actual total darkness?

 

I'm hoping this can be cleared up if I repeat one thing: My definitions of "total darkness" and the books definition of "total darkness" are different. What the book calls "total darkness" I call "really dark." What I call "total darkness" the book does not define.

 

As for the application of Nightvision, I don't assume it's just a +4 PER Only Versus Darkness Penalties for Sight PER Rolls. Yes, it cancels those penalties, but it also allows the character to see in what I call "total darkness." This is something that +4 to Sight PER Rolls-man can't do.

 

I should probably note that I've allowed characters to purchase Enhanced PER that only counters Darkness Penalties, and it costs less than Nightvision (I call it a -1 1/2 Limitation, so the cost is only 3 points) and is typically called "Lowlightvision."

[prestidigitator]

Re: Difference between Ultraviolet Perception and Nightvision?

 

In AD&D the active illumination was only visible to creatures that had infravision (active or passive), would this effect the right up? I think it would halve the limitation, IMO.

 

TB

I would say that an active sense can, by default, be detected by anyone who possesses the same sense. For example, active IR Perception can be detected by anyone with IR Perception. Active UV Perception can be detected by anyone with UV Perception. Active Sonar can be detected by anyone with Sonar. If it is detectable by a whole Sense Group and maybe other senses as well, it could take a Limitation.

[PhilFleischmann]

Re: Difference between Ultraviolet Perception and Nightvision?

 

As for the application of Nightvision' date=' I don't assume it's just a +4 PER Only Versus Darkness Penalties for Sight PER Rolls.[/quote']

But that's exactly how the book defines it! If you want it to give you something more than that, you either have to build it differently, or handwave it and say, "By GM fiat, Nightvision allows you to see in (total?) darkness better than non-limited +4 vision, somehow." The latter option may be the best course of action, but it isn't strictly by the rules.

[prestidigitator]

Re: Difference between Ultraviolet Perception and Nightvision?

 

I think of nightvision goggles as simply giving you Nightvision through a Focus. They certainly don't allow you to see in complete darkness!

[Gaelinic]

Re: Difference between Ultraviolet Perception and Nightvision?

 

In AD&D the active illumination was only visible to creatures that had infravision (active or passive), would this effect the right up? I think it would halve the limitation, IMO.

 

TB

 

What you're describing is not an active sense. From what I remember, the ability did not transmit in order to perceive. It was just described as a special effect of the infravision. That's why I'd just make it visible. But if it's only visible for people with infravision it might not be worth a limitation at all.

[Dust Raven]

Re: Difference between Ultraviolet Perception and Nightvision?

 

But that's exactly how the book defines it! If you want it to give you something more than that' date=' you either have to build it differently, or handwave it and say, "By GM fiat, Nightvision allows you to see in (total?) darkness better than non-limited +4 vision, somehow." The latter option may be the best course of action, but it isn't strictly by the rules.[/quote']

 

Mmm... seems you're right. It is bought like that. All this time I just thought is was defined like IR and UV vision was, as a seperate Detect of some sort. Silly me.

 

Well then... I hand wave GM fiat the damn thing. It's a Detect Stuff In The Dark instead of a +4 PER In The Dark now.

[Kristopher]

Re: Difference between Ultraviolet Perception and Nightvision?

 

I tend to go with a realistic approach and require the presence of some kind of light source, however dim, for Nightvision to function.

 

IMO, the difference between UV Vision and Nightvision is mainly one of SFX.

[Dust Raven]

Re: Difference between Ultraviolet Perception and Nightvision?

 

Mmm... seems you're right. It is bought like that. All this time I just thought is was defined like IR and UV vision was, as a seperate Detect of some sort. Silly me.

 

Well then... I hand wave GM fiat the damn thing. It's a Detect Stuff In The Dark instead of a +4 PER In The Dark now.

 

I've been rereading this thread and decided to reevaluate this decision of mine. For the points paid for it, I think that Nightvision works just fine like it is (though I'm penciling in the definition of "overcase, moonless night" for the book's description of total darkness). The seeing in the dark power I'm imagining should probably cost 10 points (essentially Detect Physical Objects, part of the Sight Group, but using a different SFX than light to see by).

 

This still keeps UV and Nightvision pretty much in line with each other. They do the same thing, but each can be used in situations where the other cannot.

[Kristopher]

Re: Difference between Ultraviolet Perception and Nightvision?

 

Theoretically, a sufficiently detailed form of IR vision should be able to see in total darkness (in terms of visible light) because of the very slight variations in radiant heat and IR reflectivity of different materials.

[PhilFleischmann]

Re: Difference between Ultraviolet Perception and Nightvision?

 

I think of nightvision goggles as simply giving you Nightvision through a Focus. They certainly don't allow you to see in complete darkness!

In the real world, nightvision goggles aren't based on comic-book science. Real nightvision goggles work by shifting light in the infrared (or was it ultraviolet? I forget) spectrum into the visible spectrum which you can then see. Therefore, real-world nightvision goggles should be based on infravision (or untravision? I'm sure someone knowledgable will fill us in.) through a focus.

 

All vision is based on the presense of light of sufficient intensity. If the intensity is below a certain threshold, it won't trigger the nerve cells in your retinae to fire at all, and you therefore won't see anything. Some forms of enhanced vision could be defined as lowering the threshhold for some or all of the rods and/or cones in the retina, but even then, *some* minimum amount of light is still needed.

 

Theoretically' date=' a sufficiently detailed form of IR vision should be able to see in total darkness (in terms of visible light) because of the very slight variations in radiant heat and IR reflectivity of different materials.[/quote']

But what if the surroundings are all the same material? If you're in a cave, you won't be able to tell where the walls, floor, ceiling, stalactites, and stalagmites are, because they're all the same temperature. You might be able to see where you were just leaning against the wall, because it may have absorbed some of your body heat, but that's it.

 

So what do you buy if you want to see in *total darkness*? I want to walk around normally in a cave without bumping into the walls, tripping over ridges in the floor, falling through holes, banging my head on the low ceiling, etc. IMO, this should require some form of Spacial Awareness, as part of the Sight Group (so it's Flashed along with normal sight, block by all the things that block normal sight, won't work through opaque objects, won't work if your eyes are closed or you're blindfolded, etc.). You won't have to pay for Targeting or Discriminatory, since normal Sight already includes those things.

 

And while we're at it, I'll also mention the wierd way in which N-Ray Perception is built: There is nothing in the construct that allows it to percieve through barriers - the exact function it is supposed to have!

[schir1964]

Re: Difference between Ultraviolet Perception and Nightvision?

 

...But what if the surroundings are all the same material? If you're in a cave' date=' you won't be able to tell where the walls, floor, ceiling, stalactites, and stalagmites are, because they're all the same temperature. You might be able to see where you were just leaning against the wall, because it may have absorbed some of your body heat, but that's it...[/quote']

I think, don't know for sure, but I think he was suggesting that your own body might give off enough IR to be reflected off the surfaces to enable you to distinquish them.

 

And push this concept further, not to say it is anywhere near realistic, the air currents in the cave could be seen since they wouldn't be the same temperature as the walls. And theoretically, the surfaces of the walls and floor might actually have enough variation in them to distiguish them. But this is all presuming that a person can detect changes in temperature that might be considered impossible in real life.

 

Just A Guess

 

- Christopher Mullins

[prestidigitator]

Re: Difference between Ultraviolet Perception and Nightvision?

 

In the real world' date=' nightvision goggles aren't based on comic-book science. Real nightvision goggles work by shifting light in the infrared (or was it ultraviolet? I forget) spectrum into the visible spectrum which you can then see. Therefore, real-world nightvision goggles should be based on infravision (or untravision? I'm sure someone knowledgable will fill us in.) through a focus.[/quote']

That is a common mis-conception. Real world nightvision goggles are purely light amplification devices. They use the same (or near enough to the same as makes no difference) spectrum as our eyes do. Now there are infrared devices used in a similar fashion (you commonly see applications in helicopters used by police and for wildlife tracking), but these are not, "nightvision goggles."

[Kristopher]

Re: Difference between Ultraviolet Perception and Nightvision?

 

In the real world, nightvision goggles aren't based on comic-book science. Real nightvision goggles work by shifting light in the infrared (or was it ultraviolet? I forget) spectrum into the visible spectrum which you can then see. Therefore, real-world nightvision goggles should be based on infravision (or untravision? I'm sure someone knowledgable will fill us in.) through a focus.

 

All vision is based on the presense of light of sufficient intensity. If the intensity is below a certain threshold, it won't trigger the nerve cells in your retinae to fire at all, and you therefore won't see anything. Some forms of enhanced vision could be defined as lowering the threshhold for some or all of the rods and/or cones in the retina, but even then, *some* minimum amount of light is still needed.

 

 

But what if the surroundings are all the same material? If you're in a cave, you won't be able to tell where the walls, floor, ceiling, stalactites, and stalagmites are, because they're all the same temperature. You might be able to see where you were just leaning against the wall, because it may have absorbed some of your body heat, but that's it.

 

So what do you buy if you want to see in *total darkness*? I want to walk around normally in a cave without bumping into the walls, tripping over ridges in the floor, falling through holes, banging my head on the low ceiling, etc. IMO, this should require some form of Spacial Awareness, as part of the Sight Group (so it's Flashed along with normal sight, block by all the things that block normal sight, won't work through opaque objects, won't work if your eyes are closed or you're blindfolded, etc.). You won't have to pay for Targeting or Discriminatory, since normal Sight already includes those things.

 

And while we're at it, I'll also mention the wierd way in which N-Ray Perception is built: There is nothing in the construct that allows it to percieve through barriers - the exact function it is supposed to have!

 

Real nightvision systems work by sensing ambient light, processing it, and displaying an image. Some of them will detect light from outside the part of the spectrum visible to humans, but only as a means of taking in more ambient light. Not all of the newer nightvision systems are susceptible to bright or sudden lights -- some of them will adjust or filter.

 

 

Heat is radiated as infrared (IR), which is just another form of electromagnetic radiation, just like visible light, but lower in frequency than visible light, (and higher in frequency than microwaves and radio). Just as with visible light, different materials and textures will reflect and absorb IR radiation differently. Theoretically, your own radiant heat might even be enough to illuminate a room if your eyes are sufficiently sensitive.

[Dust Raven]

Re: Difference between Ultraviolet Perception and Nightvision?

 

That is a common mis-conception. Real world nightvision goggles are purely light amplification devices. They use the same (or near enough to the same as makes no difference) spectrum as our eyes do. Now there are infrared devices used in a similar fashion (you commonly see applications in helicopters used by police and for wildlife tracking)' date=' but these are not, "nightvision goggles."[/quote']

 

Well, the term "nightvision" refers to any device that allows you to see at night, which would include light amplification (called lowlight) and IR enhancment. A few use UV enhancement, which sometimes works better because our retinas are designed to pick up UV, but our corneas filter most of it out so it is still mostly invisible to us. All these devices are nightvision, with the most common being lowlight/light amplification.

[Dust Raven]

Re: Difference between Ultraviolet Perception and Nightvision?

 

And while we're at it' date=' I'll also mention the wierd way in which N-Ray Perception is built: There is nothing in the construct that allows it to percieve through barriers - the exact function it is supposed to have![/quote']

 

Personally, I believe that N-Ray should be an adder/enhancment rather that it's own sense. Technically, the way it's bought, normal Sight should also be able to see through walls.

[PhilFleischmann]

Re: Difference between Ultraviolet Perception and Nightvision?

 

Personally' date=' I believe that N-Ray should be an adder/enhancment rather that it's own sense. Technically, the way it's bought, normal Sight should also be able to see through walls.[/quote']

Exactly!

 

And Re: How Nightvision goggles work in the real world, it appears I was mistaken. I'm glad to learn about this stuff.

 

I stand corrected, but that's only because I'm wearing orthopedic shoes.

[Killer Shrike]

Re: Difference between Ultraviolet Perception and Nightvision?

 

According to the FAQ, Nightvision works in total natural darkness including caves.

 

I just don't see why someone would buy Ultravision since the absence of any light is already offset by Nightvision. But I thank you all for your contributions.

 

Why buy a hammer when you can pound a nail with a wrench?

 

Point is, they're two different tools, and though there might be some overlap in their capabilities, they are tailored to do different things.

 

 

Nightvision is literally just like PSL's to offset darkness penalties.

 

UV Vision is the ability to percieve into a range of light normally beyond the ken of normal sight.

 

Practically they both happen to permit one to see in the dark, but they have variant pros and cons. Like the hammer is more specialized to pounding nails compared to the wrench, Nightvision is more specialized to seeing at night -- it's even in the name. That doesnt mean it's better than UV Vision overall, it's just more tailored to a specific effect.

 

The UV Vision situationally will let you do the same thing, but not as easily (requires a source of UV light), nor as safely (if you happen to be carrying around a source of UV light youre basically running up a flag to any other UV enabled people). However it also lets you see and do things that Nightvision doesnt do, which the clever player could capitalize on.

 

For instance, UV might have some forensic uses that Nightvision lacks, will see better underwater since UV light penetrates water deeper than normal light, could be used in conjunction with some blacklight paint (or similar) to leave signals for teammates w/ UV equipment that arent seeable by a large majority of people, and so forth.

 

Dont write UV Vision off as useless; just realize that if all you want to do is see better at night then Nightvision is probably the better choice.