Do almost all mammals have Bad Sight (No Fovea)?

[Sam Baughn]

I'm trying to write up some animals and after doing a few mammals and struggling to decide exactly which version of Bad Sight (if any) to give them, I discovered that only primates actually have a proper fovea and other mammals either have a flat patch or a 'streak' which serves a similar purpose.
However, a lot of mammals seem to have OK eyesight, if not quite up to human standards. Would it be fair to say that Bad Sight (No Fovea) only applies to species that have no comparable structure?
For that matter, does No Fovea even apply to species which just never had them? The description says 'the high-resolution central area of your vision has been destroyed'. That implies an eye which would normally have such an area and has now lost it, a situation which seem worse than an eye evolved without it in the first place. At the very least, the latter doesn't have a huge blind spot.

While I'm on the topic of Bad Sight, can you combine any versions except Farsighted/Nearsighted? Could you have both No Fovea and Nearsighted? Presumably you can't get full points for two versions, even if they both apply all the time, because that would be the same value as Blindness (and more than Blindness with Can Sense Light and Dark from Space p. 164, if that is still considered valid).

Also (repeating a question from a previous thread) could anyone clarify what combat penalties are appropriate for Bad Sight (Low Resolution) and Blindness plus Detect Light (Precise)? I'm inclined to say -4 on attacks for Low Resolution sight (based on the general rule of vision penalties applying to attacks) and -6 (as for Blindness) for Detect Light unless the target is brightly coloured, glowing, or otherwise really obvious. As far as I can tell, vision penalties don't usually apply to defence rolls, unless you can't see your attacker at all, so Low Resolution would give no penalty while Detect Light would give -4 (insects with compound eyes seem perfectly capable of dodging, so I can't imagine that no defences are possible).
For that matter, I'm not entirely sure what penalties apply to Bad Sight (Nearsighted). It says -2 to skill when making a melee attack. Does that imply any penalty to defence? Does 'melee' include close combat?

[whswhs]

Checking my copy of Animal Eyes, I see that human foveal resolution is 4175 cycles per radian; cats have 573, and hooded rats have 115. If you take the human figure as 20/20, cats have 20/145, and rats have 20/725. It doesn't give figures for any other mammals, but my understanding is that "mammal vision" has poorer resolution than primate vision.

However, I wouldn't call this "No Fovea"; that's designed to represent specialized injury that impairs a key function of an eye designed to use foveal vision. I would suggest using "Low Resolution," which I designed to represent mammal vision.

[Anthony]

Almost all animals (mammal or other) have worse visual resolution from humans (and other primates), though a number of raptors are significantly better than humans. I would implement most of them as having reduced vision rolls, rather than any form of bad sight, because bad sight results in DX penalties, and there's not much evidence that low visual resolution hurts animal DX very much, probably because actually hitting stuff in melee combat doesn't need high visual resolution, 20:2,000 is still 1" at a yard, which is plenty to hit a human size target.

[whswhs]

Originally Posted by Anthony

Almost all animals (mammal or other) have worse visual resolution from humans (and other primates), though a number of raptors are significantly better than humans. I would implement most of them as having reduced vision rolls, rather than any form of bad sight, because bad sight results in DX penalties, and there's not much evidence that low visual resolution hurts animal DX very much, probably because actually hitting stuff in melee combat doesn't need high visual resolution, 20:2,000 is still 1" at a yard, which is plenty to hit a human size target.

The Low Resolution version in Enhanced Senses was designerd to avoid those problems.

[Anthony]

Originally Posted by whswhs

The Low Resolution version in Enhanced Senses was designerd to avoid those problems.

The problem is that the version in Enhanced Senses isn't actually [-15] in penalties. It's maybe [-10] and arguably even less than that.

A lot of this is that GURPS grossly overstates the effects of poor vision on DX rolls, but if you fix that, bad sight is no longer worth [-15].

[whswhs]

Originally Posted by Anthony

The problem is that the version in Enhanced Senses isn't actually [-15] in penalties. It's maybe [-10] and arguably even less than that.

A lot of this is that GURPS grossly overstates the effects of poor vision on DX rolls, but if you fix that, bad sight is no longer worth [-15].

That might be an argument for changing the published book. But it's not an argument for not using the trait as defined there. That's a question of whether the trait's definition (a) fits the real world facts and (b) addresses the game mechanical concerns.

[Sam Baughn]

Originally Posted by whswhs

The Low Resolution version in Enhanced Senses was designerd to avoid those problems.

So Low Resolution gives no penalties in combat?
Is that also the case for Blindness with Detect Light (Precise) or does that use the usual rules for blindness?

[Anthony]

Originally Posted by whswhs

That might be an argument for changing the published book. But it's not an argument for not using the trait as defined there. That's a question of whether the trait's definition (a) fits the real world facts and (b) addresses the game mechanical concerns.

The trait's definition in ES is approximately telescopic vision -4, so 20:450 vision or so. It has something of a granularity problem but is a match for at least some specific animals.

[Sam Baughn]

Originally Posted by Anthony

The trait's definition in ES is approximately telescopic vision -4, so 20:450 vision or so. It has something of a granularity problem but is a match for at least some specific animals.

Acute Vision, Perception, Telescopic Vision, etc. offer a lot of options to tweak it back up for the species which lie between primates and rodents in terms of visual acuity.

[Maz]

Originally Posted by whswhs

That's a question of whether the trait's definition (a) fits the real world facts and (b) addresses the game mechanical concerns.

slightly off topic but.

I am really nearsighted (-7 or something like that, I can't even remember it exactly). I have played a lot of live role playing (running around the woods hitting people with buffer swords). I always wear glasses or contacts.

One time I had to fight without them on*.

And compared to normal, I was at a significant disadvantage! I was able to se the blurry shape of my opponent and know were they where. But I couldn't accurately read the movements of their weapon. And distinguishing between friend and foe in my peripheral vision was impossible.
I also kept stumbling over roots or rises in the forest ground.

So by this logic I think the DX penalty in combat makes sense for nearsightenness.



*I lost one contact and decided to remove the other as well - it was making me queasy to have mixed vision and it was annoying to keep one eye closed all the time. I had my glasses back in camp anyway. However on my way back to camp to get my glasses, I ran into a fight.
Today I would probably just have used my scarf as a blindfold for that eye.