[ZeConster]

So I'm looking at the Environmental Compensation list, and I'm wondering if (and if so, how) different things affecting the same condition stack.

• I'm assuming that if they stack, you take them as a whole (so Thermographic Vision + Sunglasses gives Light one row up and one row down, so it stays the same regardless of which row you're in, while Flare Compensation + Sunglasses gives Glare three rows up, making you completely immune to it), instead of applying them one by one (which would mean that Thermographic + Sunglasses either turns Total Darkness into Dim Light because you apply the Sunglasses first, or turns Full Light into Partial Light because you apply the Thermographic first)?
• I'm assuming that Low-Light, Thermographic and Ultrasound are mutually exclusive?
• If you combine Low-Light with Sunglasses, what happens? Do you treat Dim Light and Partial Light as Full Light because of the Low-Light, then shift it down one row to Partial Light because of the Sunglasses? Or do the Sunglasses turn Dim Light into Total Darkness, meaning Low-Light no longer affects it? In other words, do the modifiers become -1/-1/-1/-6, or 0/0/-6/-6?

[Linkdeath]

Wow, tricky question! I'll give it my best shot, and this is just how I'd rule on it at my table, if this came up.

So I'm looking at the Environmental Compensation list, and I'm wondering if (and if so, how) different things affecting the same condition stack.

• I'm assuming that if they stack, you take them as a whole (so Thermographic Vision + Sunglasses gives Light one row up and one row down, so it stays the same regardless of which row you're in, while Flare Compensation + Sunglasses gives Glare three rows up, making you completely immune to it), instead of applying them one by one (which would mean that Thermographic + Sunglasses either turns Total Darkness into Dim Light because you apply the Sunglasses first, or turns Full Light into Partial Light because you apply the Thermographic first)?

I'd say that regarding light levels, you would indeed stay at the same level, since the two cancel each other out in that regard. Since the light has to go through the sunglasses before they get to your eyes, I'd say you apply the modification of the sunglasses first.

• I'm assuming that Low-Light, Thermographic and Ultrasound are mutually exclusive?

Not at all. You can certainly have them all, as they are useful for different things. Low-light is good for seeing at a distance in dim conditions, even better than thermo. Thermo is good for improving visibility and light conditions both. And while it doesn't give as much a benefit as low-light, thermo can also work in total darkness, unlike low-light. And finally ultrasound beats them both with light, but only out to 50 meters, meaning anything at a decent distance will be as obscured as an unaugmented person. I'd actually say thermo and ultrasound are as good as each other for visibility (though there's no smoke for blocking ultrasound).

• If you combine Low-Light with Sunglasses, what happens? Do you treat Dim Light and Partial Light as Full Light because of the Low-Light, then shift it down one row to Partial Light because of the Sunglasses? Or do the Sunglasses turn Dim Light into Total Darkness, meaning Low-Light no longer affects it? In other words, do the modifiers become -1/-1/-1/-6, or 0/0/-6/-6?

Ruling at my table, I'd say that if you wore sunglasses with low-light, as long as you weren't in dim light or worse, you could see just fine. In dim light, the sunglasses would turn it into total darkness by the time your actual eyes got to see anything. In effect, the sunglasses would block all available light, giving your eyes nothing to work with. So I'd say 0/0/-6/-6. I think there are examples of that in the fiction, actually, like the elf who wears sunglasses, even in a room only partially lit, but seems to be able to see just fine.

[ZeConster]

I'd say that regarding light levels, you would indeed stay at the same level, since the two cancel each other out in that regard. Since the light has to go through the sunglasses before they get to your eyes, I'd say you apply the modification of the sunglasses first.

So you'd rule that the sunglasses worsen the Total Darkness, only it can't get any worse, and then Thermographic turns that into Dim Light?

• I'm assuming that Low-Light, Thermographic and Ultrasound are mutually exclusive?

Not at all. You can certainly have them all, as they are useful for different things. Low-light is good for seeing at a distance in dim conditions, even better than thermo. Thermo is good for improving visibility and light conditions both. And while it doesn't give as much a benefit as low-light, thermo can also work in total darkness, unlike low-light. And finally ultrasound beats them both with light, but only out to 50 meters, meaning anything at a decent distance will be as obscured as an unaugmented person. I'd actually say thermo and ultrasound are as good as each other for visibility (though there's no smoke for blocking ultrasound).

You can have more than one of them, sure, but I meant that I assumed you can't have more than one of them active at the same time, so stuff like Low Light + Thermographic.

[Linkdeath]

I'd say that regarding light levels, you would indeed stay at the same level, since the two cancel each other out in that regard. Since the light has to go through the sunglasses before they get to your eyes, I'd say you apply the modification of the sunglasses first.

So you'd rule that the sunglasses worsen the Total Darkness, only it can't get any worse, and then Thermographic turns that into Dim Light?

Actually, I'd assume you started stacking modifiers at that point, and drop to -10, so then thermo would get you back up to total darkness and -6. But then I can be a jerk GM sometimes 

• I'm assuming that Low-Light, Thermographic and Ultrasound are mutually exclusive?

Not at all. You can certainly have them all, as they are useful for different things. Low-light is good for seeing at a distance in dim conditions, even better than thermo. Thermo is good for improving visibility and light conditions both. And while it doesn't give as much a benefit as low-light, thermo can also work in total darkness, unlike low-light. And finally ultrasound beats them both with light, but only out to 50 meters, meaning anything at a decent distance will be as obscured as an unaugmented person. I'd actually say thermo and ultrasound are as good as each other for visibility (though there's no smoke for blocking ultrasound).

You can have more than one of them, sure, but I meant that I assumed you can't have more than one of them active at the same time, so stuff like Low Light + Thermographic.

Actually, I assumed you could indeed have more than one running at a time. Why else would you be able to stack them in cybereyes? Take for example the Street Sam archetype in SR5, p.112. He has cybereyes with flare comp, low-light and thermo, all at the same time.

[Crunch]

Stacking in cybereyes (or vision mods) is more about having "swiss army vision" where the correct choice is always available.

[Xenon]

I'm assuming that if they stack, you take them as a whole

That is how I understand it as well.

...while Flare Compensation + Sunglasses gives Glare three rows up, making you completely immune to it

That is how i understand it as well.
(strange that low light does not shift glare one row down)

Special case with flash-pak:
This give you -4 dice
Or -2 dice if you have flare compensation in goggles or glasses
Or -1 dice if you have flare compensation as eyeware
No idea if and if so how sunglasses interact with this.
Either it make you immune in both cases or you still have -1 dice in the first case.

I'm assuming that Low-Light, Thermographic and Ultrasound are mutually exclusive?

ultrasound headware replace/override your vision. p.452
(ultrasound is also not a vision enhancement)

low light and thermographic might or might not do that as well (think predator).

low light enable you to see light levels as low as starlight (like a cat) and thermographic let you see the infrared spectrum, from a semi-realistic point of view they technically don't need to be mutual exclusive.... but if they are not mutual exclusive then they should probably not stack.

you can combine other visual enhancements just fine and there is no explicit text that prevent you from combining low light and thermographics. or low light and flare compensation. or vision magnification and thermographic vision. or....

however, right or wrong I personally always used the predator approach;
normal vision or low light vision or thermographic vision or ultrasound "vision"
(then again i am a fan of predator so i might be biased)

If you combine Low-Light with Sunglasses, what happens?

with sunglasses and low light dim light become total darkness and low light can't help you. take off your sunglasses and you will have full light.

[Michael Chandra]

Actually, I'd assume you started stacking modifiers at that point, and drop to -10, so then thermo would get you back up to total darkness and -6. But then I can be a jerk GM sometimes 

It's also violating the rules: You can't go past -6 on a single modifier.