Cavern Generator

Here is a generator for a set of Caves, Caverns, or as I like to call them Adventure Holes. 

It was built for +Alex Chalk 's mountainy hex crawl which is "rocky and lightly forested in parts". Caves can go anywhere though and if you don't have caves in your campaign your're doing it wrong. 

I prefer my description and content tables vague, so even if you get the same or similar combination allow your mind to fill in the gaps and make up something different each time. 

Further to that, you will find reference to an "Aspect table" on some results, this is my catch all inspiration table that you can use to jolt your creative organs into spewing out some further details about a result. You will find this table at the bottom of the page.

Some of the tables are slightly obsessive, featuring things like number of exits and exit/entrance locations. This is mostly because I wanted to generate some excitement in traversing between caverns. Also I think Alex wants to have a focus on climbing and vertical challenges in his campaign and the exits and linking tunnels give scope for this. 

If I was using this at the table to generate things on the fly I would probably only roll on: 

• General/Overall Vibe of Cavern System
• Specific Descriptors of Individual Caverns
• Cavern Content

(Thanks +Arnold K. for getting the ball rolling with the Cavern Entrances [ I slightly added to these and d100'ified because I have a total boner for d100's]) 

Cavern Generator:

Overall Cavern System:

Cavern System Entrance: 

0 - 10) Broad, classic entrance, sunlight floods first cavern
11 - 19) Narrow crevice, no fatties allowed
20 - 28) Steep hole, tumbling or rock fall risk
29 - 38) Vertical hole/cliff down
39 - 48) Covered in ferns or other vegetation 
49 - 47) Menacing wasp, insect or other pest nest/hive covering entrance
48 - 56) Entrance visible but mostly blocked by dirt or debris 
57 - 66) Suspicious signs of habitation
67 - 76) Entrance d10 x 10' off the ground
77 - 86) Slippery with guano or other droppings  
87 - 95) Mountain stream exits here, cavern system filled with streams and pools
96 - 99) Worked stone steps

Total Number of Caverns:

0 - 15) 1

16 - 40) 2

41 - 60) 3

61 - 75) 4

76 - 90) 5

91 - 99) 6

Shape of Caverns:

0 - 24) Pit (All exits can be Vertical or Steep Descents)

25 - 51) Domed (All exits can be Vertical or Steep Ascents)

52 - 80) Rectangular

81 - 90) Spherical

91 - 99) Winding Tunnel (Convert the size of the Cavern to a long winding 10' x 10' tunnel)

Light Source In Cavern System:

0 - 10) Lots of natural light

11- 30) Very dim natural light

31 - 90) Pitch black

91 - 99) Lit by an unnatural light source (could be something spooky or might just be torches, roll on the Aspect table for inspiration).

General/Overall Vibe of Cavern System:

0 - 2) The caverns are a living thing. The walls are fleshy, there is evidence of veins, tongues, teeth, etc.

3 - 5) Lava, very hot, pools and streams of the stuff.  

5 - 13) Crystals or crystalline minerals protruding from walls.

14- 21) Veins of attractive looking minerals.

22 - 29) Soft looking, rolling rocks and boulders (probably Granite)

30 - 38) Sandy and porous rock (probably Limestone)

39 - 47) Rock type specific to campaign area (you know it best, or roll on Aspect Table)

48 - 57) Wet caverns, filled with lots of pools and dripping stalactites.

58 - 66) Roots protruding through rock, lots of veins 

67 - 75) Smooth Marble

76 - 80) Cavern walls and ceilings covered in markings, symbols or graffiti  

81 - 85) An abundance of vegetation, mostly ferns and Fungi  

86 - 90) Seemingly abandoned humanoid habitations;  beds, shacks, firepits, rags, refuse, graffiti, furs, etc

91 - 95) Seemingly abandoned animal habitation; nests, skins, fur, hair, eggs, holes, droppings, etc. 

96 - 99) Ruins, protruding from walls or filling caverns (Roll a d%, ruins are: 0- 20) human, 21 - 41)dwarf, 42- 62) Rockman, 63 - 83) Elven, 84 - 99) Mysterious other)

Specific Caverns:

Size of Cavern:

0 - 10) Tiny 10' x 10'

11 - 30) Small : 30' x 40'

31 - 60) Medium: 50' x 50'

61 - 75) Large: 70' x 70'

76 - 99) Humongous: 100' x 100'

Number of Exits: Keep making exits until you have reached your Number of Caverns quota. Unused exits can link to other caverns to give that cavern extra exits. Alternatively you can make the caverns link however the hell you want.

0 - 37) 1

38 - 75) 2

76 - 99) 3

Exit Location:

0 - 12) On the lowest part of the floor

13- 26) On the highest point of the ceiling

27 - 50) Left of Original Entrance

51- 75) Right of Original Entrance

76 - 99) Opposite Original Entrance

Exit Ascent/Descent and Length (Linking Tunnel): Lengths may or may not be useful depending on the emphasis on the danger of climbing.

0 - 16) Vertical Ascent (cliff) 1d10 x 10' high

17 - 31) Steep Ascent, 1d10 X 10' long (Dex. check chance of stumbling and falling backwards)

32 - 46) No linking tunnel, caverns open up to directly next to each other

47 - 69) Flat, 1d10 x 10' long

70 - 84 ) Steep Descent, 1d10 x 10' long (Dex. check chance of stumbling and falling forwards)

85 - 99)Vertical Descent (cliff), 1d10 x 10' deep

Features of Linking Tunnel:

0 - 8) Tiny tunnel (humans will have to crawl/squeeze tunnel is human waist high)

9 - 20) Small tunnel (Maximum 1 person abreast)

21 - 30) Dry, dusty rock (no special features)

31 - 39) Slippery, wet or otherwise moldy rock

40 - 48) A stream/river (waterfall on cliff up or down)

49 - 58) Hard, jagged crystalline minerals formation (great for climbing, alternatively may cut climbing ropes)

59 - 68) Bats, insects or other assorted pests (will rush past the party, probably at the worst possible time)

69- 78) Vegetation (most likely mushrooms and ferns, may make finding foot/hand holes harder for climbing)

79 - 85) Change of light condition (re-roll on light table)

86 - 95) Old, used ropes or hanging vines/roots.

96 - 99) A trap (tumbling rocks, hidden spike pit, shooting darts, etc)

Entrance Location in Next Cavern:

0 - 17) Top

18 - 35) Bottom

36 - 53) North

54- 71) East

72 - 85) South

86 - 99) West

Specific Descriptors of Individual Caverns (Roll for Each):

0 -5) Smoke or gas (could do something nasty, helpful, or weird. Roll on Aspect table)

5 - 10) Overgrown vegetation choke this cavern (mushrooms/ferns/roots that must be hacked to continue)

11 - 14) Suspicious mushrooms or cavern fruit (could be benign, valuable or harmful. Roll on Aspect Table)

15 - 20) Weird noise or smell (Roll on Aspect Table)

21 - 25) Statue or statues (Roll on Aspect Table)

26 - 30) Viewing platform of forest/mountain (if an Ascended Cavern) viewing platform of ridiculous huge cavern (if in a Descended Cavern)

31 - 35) Large whirlpool

36 - 40) Humongous crystal (Roll on Aspect Table)

41 - 45) Honeycombed with holes and drops (in ceiling or floor, probably deadly or could lead to another cavern)

46 - 50) Cavern cut in half by crevice of a very deep nature

51 - 55) Lots of candles or assorted religious paraphernalia

56 - 60) Stalactites/stalagmite maze

61 - 65) Stalactite/stalagmite Pillars

66 - 70) Hordes of vermin

71 - 75) Unusually smooth walls, floors and ceilings. The stone has been polished.

76 - 80) Graveyard or Burial Ground

81-85) Large well-constructed nest or burrow

86-88) Large well-constructed hideout, shack or mini-fort

89 - 90)Altar (roll on Aspect Table)  

91 - 92) Gathering place (roll on Aspect Table)

93 -94) Floating Rocks

95 - 96) One side of the cavern has an elaborate and huge piece of art (painting, carving,etc. Roll on Aspect Table)   

97 - 98) The ceiling opens to the outside world. The cliff separating outside and the cavern floor may be very, very tall. Sunlight floods the cavern.

99) Climate Change cavern (Very hot, very cold, very wet, etc)

Cavern Content (Roll for each):

0 -8) Wandering Monster, aggressive

9 - 17) Wandering Monster, aggressive (holds or guards treasure)

18 - 30) Empty

31 - 39) Wandering Monster, willing to parley

40 - 48) Treasure

49 - 50) Hidden Treasure

51 - 56) Lunatic, hermit or bard

57 - 59) Holy people, monk, nun or priest 

60 - 64) Bandits, degenerates or mutants.

65 - 70) Spelunkers, treasure hunters or other adventurers

71 - 75) Meditating, celebrating or studying Rockmen

76 - 83) Dwarfs mining, burrowing or building

84 - 89) Human geological survey crew, miners or other industrial group

90 - 95) Animals

96 - 99) Cultists, con artist or thief

Aspect Table: 

000-9) Good/holy/light
10-19) Air/ethereal/wind
20-29) Tiny/invisible/intangible
30/39) Value/thought/internal organs and reflection
40-49) Water/equalization/cleansing
50-59) Wild/bestial/nature
60-69) Fire/destruction/limbs and external action
70-79) Monstrous/gargantuan/enormous
80-89) Deep/earth/solid
90-99) Evil/profane/darkness