If you’re walking in on the middle of the advanced fantasy dungeon series, there’s an index here.

Vision gets a lot of time in second edition:

• Visibility by size and distance in optimal conditions outdoors
• Visibility by weather condition
• Visibility while moving
• Light source radius, direction and speed of exhaustion
• Fighting with mirrors
• Light reducing chance of surprising
• Darkvision vs Infravision vs Ultravision
• Darkness’ effect on movement
• Invisibility

The main principles to be drawn from this it appears are that vision impacts actions like movement, spell casting, combat, and surprise and that vision is a resource in darkness indoors or outdoors.

If vision is a resource, there should always be a trade off. The obvious ones are inventory slots, money, spell slots and combat advantage.

• Light sources (torch, lamp, spells) are used to provide vision
• Fuel (oil or torches) is bulky to carry
• Light spells take up spell slots and space in a spell book
• Holding a light source causes a combat disadvantage and means you’ll always be seen first

I like the idea of spell books having a limited number of spells (not small but a high level wizard is likely carrying 5 spell books taking up 5 inventory slots), so part of the limitation of being a wizards is the library you’ll have to carry.

I’d like to simplify vision as well, because different distances for different light sources is challenging. But some granularity is fun.

• In daylight or equivalent, you can identify things not obscured (not hiding, behind things, etc) in your field of vision to a reasonable distance.
• In twilight or equivalent, you can see as daylight in your field of vision up to a stone’s throw away.
• In darkness or equivalent (fog, blizzard), you cannot identify anything visually.
• A light source allows you to see as twilight.

The “reasonable distance” is intentionally obscured (its 1km, right there is the PHB), to simplify the rules. A “stone’s throw” also intentionally vague (it’s 10-20m, also in the PHB), for the same reason. I don’t want a spell to provide “two stones throws” of light. I want normal rooms to be illuminated easily, vast chambers to be creepy, and chasms to be bottomless. Also “Portable Twilight” is a great magic item name.

Finally, second edition differentiates darkvision (uncomplicated variant, similar to fifth edition), infravision (heat-sensing), and ultravision. Interestingly, I think the designers preferred darkvision (“can see in the dark”), but it breaks the cardinal principle of the vision section that they set: Vision is a resource. I want to keep the simplicity but create a downside to being same to see in the dark.

• If you have infravision or ultravision, you do not have standard vision (whether this is permanently, due to your heritage, or temporarily, while under the effects of magic).
• If you have infravision, you see heat instead of light. You see in darkness as daylight and see daylight as darkness. In darkness and twilight, you can see additional features such as heat-trails and warm air currents. You are blinded by a sudden lit torch or a glance at the sun for a turn. If it is cold and you wear shaded lenses you can see as twilight during the day.
• If you have ultravision, you can see in starlight and in indirect sunlight as daylight. You see direct sunlight and darkness underground as darkness. Your eyes glow, and under your gaze white items glow as well. Magic items and spells are visible to you at a stone’s throw.

Dwarves have infravision, so are only come out in the evenings in most climates, but there are cities of dark-lensed dwarves in the frigid north. Elves have ultravision, and hence would avoid depths and stay in places – like forests – that light is filtered from. I’m not sure if I’ve hit the sweet spot here, mainly because ultravision is messy and inessential but messiness is fun (some of the ultravision stuff is from this article which is nameless and authorless).

Invisibility should work as advertised, but I love that I can make it perfect invisibility because I’ve written in a giant flaw: “Elves can see invisible people”. Mirrors should work as advertised, and honestly I’m going to let mirror-wielding heroes fight medusa without any more than the same penalty they’d get for carrying a torch. Surprise really belongs elsewhere, so I’ll have to remember this little rule when I get there.

This has been a part of the Advanced Fantasy Dungeon Series! Let me know your thoughts on vision, if there are questions left unanswered, whether I’ve overlooked anything glaring, or anything of the sort!

Idle Cartulary

16th April 2022