Sight Cones and Sound Spheres

I have a plate mail problem. And no, it’s not chafing and yes, I know about the baby powder trick. It’s noise. Or rather, it’s a false perception that my players have – they have got it in their heads that if even one party-member is wearing shiny, clanky plate mail or hasn’t super-specialized in stealth stats that they will make so much noise while moving that every sentry in the castle will instantly see and hear them and rush from their post to commit murder. They have made an assumption that avoiding sight and quiet movement is impossible unless you’re a fully trained ninja and infiltration tactics are off the table before the mission-planning even starts. So, how do I re-educate them on the soundness of soundless-and-sightless strategies? A visual aid from the world of video games is the answer!


I was first introduced to the idea of the sight cone or vision cone from a game called “Shadow Tactics: Blades of the Shogun,” which developed the idea from previous games in the “Commandos” and “Desperados” lines. “Shadow Tactics” is a game about ninjas and samurai who need to sneak around, avoiding and dispatching guards while completing objectives. The player’s perspective is an overhead view, so a visual aid is necessary to indicate where a guard’s gaze is pointed. Enter: the sight cone.

The sight cone is a green wedge that starts at the face of the guard and projects outward into the landscape. It’s about as wide as a person’s field of vision and it drops off after a certain distance to indicate that they aren’t focusing their attention more than about a dozen meters out. Most importantly, the sight cone is blocked by objects that would block sight, such as walls, large crates, doors, and even bright bonfires at night. Anything suspicious that happens inside this sight cone may trigger a reaction from the guard. If it happens outside the cone, they simply don’t see it.

Brilliantly, Mimimi Productions added a low cover mechanic into this schema – anything that would partially obscure vision (bushes, barrels, dim light, distance, etc.) causes the green cone to turn into a banded line pattern. A sentry still has a chance to spot enemy actions within this area, but the chance is much lower and their reaction time significantly slower. Several missions in the video game have the player snuffing out light sources to create these obscured areas so they can slip through more easily.


So, how does this work for a table-top game? Well, if you’re already using digital battle maps, you can add another layer and draw some semi-transparent wedges on there (lower the opacity of the color or the layer so they’re partly see-through). If you’re using a physical map, you can try drawing on the map itself (if they’re paper or dry-erase). But this will require re-drawing every time the guard moves their head. A little flashlight pointed at just the right angle could indicate a sight cone very aptly. A paper, cardboard, or fancy laser-cut acrylic template could also work, though you may have to slide it over or under minis and terrain props. If you already have spell-effect templates, just use one of those. A simpler version might be just to grab some chopsticks to indicate the edges of the field of vision. It has the advantages of being very cheap and very easy to reposition. You could break or cut them down to the size you need, or even paint them different colors for different guards (just don’t eat with them afterward). And if you’re playing theater-of-the-mind style, you can describe the patterns of the gazing guards as part of your room layout.

Rules-wise, assume that anything visual that happens outside of the cone cannot be seen by the guard in question. Anything inside the cone has a chance to be spotted according to the rules and anything within a “partial cover” field of view has whatever modifiers are appropriate for the game and situation.


A sound sphere or sound circle is a bit different. It is a spherical burst that extends outward from the source of a noise – like a paladin running in plate mail – and it’s overall diameter varies by how loud it is. Noise-blocking objects like walls or doors dampen the sound. Other noises like waterfalls or singing bards muddle it so it is indistinguishable. But whenever a sound sphere intersects a guard’s ears, they have a chance to hear it and react.

To help my gaming group visualize their noise and be less afraid of wearing heavy armor on the stealth mission, I might create a sound circle template based on their natural noise level. Again, this could be a drawing, physical template that fits around their miniature, flashlight circle shone from above, etc. An armored knight who has taken no precautions to secure the array of steel weapons that bang against his greaves would have a very large sphere. The rogue in cloth who has carefully fastened every loose item in his utility belt would have an extremely small or perhaps even a non-existent sphere.


In game terms, I would suggest that an average person wearing average clothing, average gear, and taking no special precautions to prevent noise would emit a sound sphere at a radius of about 50 feet or about 15 meters. Halve that (at least) for people trying to sneak. Anything noisy that gives a penalty to Stealth increases the diameter of the sphere, and vice-versa with bonuses. You can make up some complex rules based on your game system, but I would simplify it and increase or decrease the radius in 10 foot (@ 3 meter) increments for each modifier or noise-source that was added or subtracted. If a sentry is outside the radius, they generally don’t hear much. Within the sphere, follow the rules for Stealth for your game.

Sight cones and sound spheres are a useful mental mechanic for visualizing a character’s sensory effects, and have the potential to teach players the simulated physics of the world in which they’re gaming. Next time you want to add some spectacle to your stealth scene, break out the shapes!

Award Winning!

Gold ENnie for Best Website 09'-11'

Silver ENnie for Best Website, Best Podcast 2012-2013
Petrified Articles
© Copyright 2010-2024 Words In The Dark. All rights reserved. Created by Dream-Theme — premium wordpress themes. Proudly powered by WordPress.