Friday, July 13, 2018

Monstrous Senses

Today I’ll be talking about senses. As it stands, we have a few advantages and disadvantages that work well to describe different ways humans can or could perceive the world around them, but we start to run into problems when we try to extend these to animals. And if we can’t even stat up a dog’s senses, what are we missing out on when we make monsters?

“But senses aren’t what makes a monster deadly!” I hear you yell angrily at your monitor. That’s not entirely true. If a monster can spot you before you spot it, it can catch you unawares and unable to defend yourself – for one round, at least. And that can be enough to put you into a death spiral. What’s worse is that a monster in its natural environment will probably sense you just fine, even if you can’t figure out where it is!

“But I have smoke bombs that will block its vision!” you reply. Well, not all monsters use vision as their primary sense. What about beasts that smell as well as humans see? Or those with such amazing hearing that they can fight by sound alone? Maybe they can feel where you are based solely on your footfalls. See where I’m going with this? An easy way to give a monster an interesting and substantial advantage is to give it special(ized) senses. That means we need traits to describe them.

How Much Is a Sense Worth?

First thing to address is simple enough. What is Vision as a sense worth? What about Hearing? “Wait! These are for monsters, so why do we care what they are worth?!” Good catch, but for completeness – and use when making power-ups – this can be useful information to have. If you never intend to let a PC buy these modifications to their senses, then this bit is pretty worthless, but if you think they might get access to power-ups or abilities that could take advantage of these, read on!

So back to the original question: What is a sense worth in character points? We don’t have advantages or attributes that explicitly tell us this, but what we do have are disadvantages that tell us what not having a sense is worth. By that measure, we can infer the value of a sense as being the number of character points it takes to buy off the disadvantage. There is precedent for this in the cybernetics builds in GURPS Ultra-Tech.

So cool, let’s see what the basic five senses are worth:
  • Vision. Based on Not Blind: 50 points.
  • Hearing. Based on No Deafness: 20 points.
  • Smell. Based on No No Sense of Smell/Taste (Smell Only, -50%): 2.5 points.
  • Taste. Based on Not No Sense of Smell/Taste (Smell Only, -50%): 2.5 points.
  • Touch. Based on Not Numb: 20 points.
My immediate reaction to these costs is that Smell is underpriced, Taste doesn’t seem too far off, and Touch is overpriced. I say this overall relative to each other. Is being able to see worth 50 points? I’d say it’s definitely useful, but I’m not 100% sure.

“But Bill Stoddard addressed all of this in Normal Senses and Modifiers (GURPS Powers – Enhanced Senses, p. 9)!” Yes, you’re right, and thank you for the page reference! We are simply looking at an alternate way of computing this so we can make an educated decision on how to approach this. Working his numbers backwards, we see that he had these priced as follows:
  • Vision. Based on 100% enhancement times 1/5: 20 points.
  • Hearing. Based on 100% enhancement times 1/10: 10 points.
  • Smell. Based on 100% enhancement times 1/50: 2 points.
  • Taste. Based on 100% enhancement times 1/50: 2 points.
  • Touch. Based on 100% enhancement times 1/10: 10 points.
Well, it looks like Bill agrees about Taste and Touch, but he disagrees about Smell. He also lowered the price of Vision, which I’m not totally against. This is as good a time as any to mention that the price of a disadvantage is not simply the inverse of the price of a similar advantage. Sean Punch has mentioned this numerous times on the GURPS forums, and it’s worth saying again here.

So now we have two pricing schemes that don’t completely agree with each other. I’m going to defer to Bill’s pricing not only because it bore both the scrutiny of the playtesters and the editorial staff, but because it feels more in line with what makes sense.

Sense Modifiers

Now that we know what our base senses cost, let’s take a look at a few useful modifiers and create a few more for good measure. From Enhanced Senses, we have Long, +20% per +1 to SM (p. 9); Microscopic, +25% (p. 9); Nondirectional, -25% (p. 9); Precise, +100% (p. 8); Restricted Arc, Varies (p. 9); Targeting Only, -40% (p. 8); Targeting, +20% (p. 8); and Universal, +50% (p. 8). GURPS Powers has Long-Range, +50% (p. 108-109); Profiling, +50% (p. 47); Short-Range, -10% (p. 112); and Stethoscopic, +50% (p. 73). Lastly, GURPS Basic Set gives us Extended Arc, Varies (p. 82); Precise, +100% (p. 48); and Vague, -50% (p. 48).

We also need one more enhancement: Imaging. We will base this on Sensitive Touch, which costs 100% of Touch. Thus, Imaging, as defined in The Sensory Hierarchy, (Enhanced Senses, p. 6-7) will be an enhancement that costs +100%. And with that, we should be able to create whatever senses we need for our monsters.

Lastly, we need a Nondiscriminatory limitation for vision. Thinking on it, nondiscriminatory vision feels about as useful as standard hearing. You can kind of generally tell where things are, you can kind of tell things apart, but you have a hard time resolving details and you can't really do intricate work by it. This would bake in the general -4 penalty to use nondiscriminatory senses for things that would require discrimination. Considering it usually takes 15 points to make non-discriminatory sense into a discriminatory one, that's [-15]. I think that's a good ballpark cost, possibly being about [-5] shy of reasonable. I'm okay calling "Nondiscriminatory" a -75% limitation that, when applied to Vision comes out to a -15 point disadvantage.

Some New Advantages

A few particular new advantages are worth defining here. One group is based on See Invisible, and the others will just see a fair amount of use in monster templates.

Long-Range Smell

1 point
Your sense of smell uses the range penalties from the Speed/Range Table (p. B215) instead of the usual penalties.

Precise Hearing

10 points
Your sense of hearing is sufficiently precise to target opponent in combat by sound alone. This means you no longer must rely on vision – or take Vision penalties – on your combat skills. This does not include any form of echolocation, but you can use other people’s echolocation to find them at twice its normal range!

Sense the Unsensable

The first thing we will do to create a handful of new traits based on See Invisible. This advantage costs 15 character points and lets the user visually perceive one class of invisible things. There are plenty of examples of things “invisible” to hearing, smell, and touch – e.g., anything with Insubstantiality. Considering that See Invisible is 75% the cost of Vision as we determined above, we can use this to Hear Silent [8], Smell Ordorless [2], and Feel Intangible [8]. These can all take True Sight, +50% as described in Powers, p. 73.


10 points
You can feel your surroundings within one yard. Your tactile sense still too vague to distinguish fine detail, but you can navigate without running into things and fight just fine. You must choose whether your whiskers work in air or in water upon taking this advantage. Air whiskers take penalties for strong winds and don’t work while immersed in liquids; water whiskers take penalties for strong currents and don’t work while in air.

This is built as Vibration Sense (Air; Melee Attack, -35%) [10].

Some New Disadvantages

If we are to model most mammals’ vision, we will need a finer gradation to Bad Sight than currently exists. And while we are at it, we can go ahead and create new versions for every sense.

Bad Sight

-5 points / level
You have unusually poor vision. Each level of Bad Sight gives a -1 penalty to Vision rolls.


Mitigator. Some device corrects your vision sufficiently to see normally. A typical pair of glasses or contact lenses is -60%.

Near-Sighted. This half your penalty to all Vision-dependent activities from 1 to 2 yards away and full penalty beyond that. This means you can’t read small print at more than a foot away or signs more than about ten paces. This effectively results in taking half your penalty to melee attacks and full penalty to ranged attacks. -50%.

Far-Sighted. You take your full penalty to all Vision-dependent tasks within one yard, reduced to half your penalty if you would be aided by another sense, like your sense of Touch – e.g., woodworking, close combat, etc. You also have difficulty reading any small text; triple time requirements, if it matters. -50%.

Motion-Sensitive. You have difficulty distinguishing between the foreground and background. This penalty only applies to stationary objects; you can still easily see anything that is moving. -50%.

Bad Hearing

-2 points / level
Your hearing is unusually poor. Each level of Bad Hearing gives a -1 penalty to Hearing rolls.

Bad Sense of Smell

-1 points / level
You have a particularly difficulty time noticing and distinguishing odors. Each level of this disadvantage gives -1 to Smell rolls.

Bad Sense of Taste

-1 points / level
You have an especially unrefined pallet. You are at -1 to all taste rolls.

Bad Sense of Touch

-2 points / level
Your tactile sense is surprisingly poor. You are at -1 to all Touch rolls.

So What Was the Point?

Now we have a group of sensory traits and modifiers we can use to more fully flesh out beasts and monsters in a way that makes them feel different than just another human-with-abilities. GMs who play up the enemy’s ability to detect and track the PCs will create more memorable and terrifying encounters, and that’s what we want!

As I begin to post creatures for Starfall, I will use these traits and modifiers and link back to this post as a reference. I’m also looking at modifying the standard monster block from Dungeon Fantasy to flow better for GMs. I’ll post more on this later, but if I go through with it, parsing out these traits will have been more than worth the effort.

Did I miss anything major here? How have you used senses in your games? Leave your thoughts and comments below!


  1. One thing from my recent work is that a monster’s senses may be better or worse than a human’s, but then not being the same makes them seem even more monstrous.

    1. This is true and exactly why I included ways to reduce individual sense scores; we needed an inverse of Acute (Sense). The other modifiers further let us shape monster senses up and down from the human norm, too.

      One thing worth saying, though, is that any predatory or prey monster will likely have at least one sense that is as good as human vision and probably at least another that is as good as human hearing. This is because predatory mammals exist. In a non-ecological way, it is because it's kind of easy to fight a monster that doesn't know you're there. Of course, some monster concepts justify this, but those are generally few in my experience.

      I'm curious to see how your recent work uses senses to shape interactions with your monsters.