d20 UPPs

[TKalbfus]

I have an idea for generating planets using 20 sided dice instead of 2d6s.
First the Starport type:
D20
Result Starport
1 A
2 A
3 A
4 B
5 B
6 B
7 B
8 B
9 C
10 C
11 C
12 C
13 C
14 C
15 D
16 D
17 E
18 E
19 E
20 X

For size we go metric (km)
Digit Description
0 Asteroid/Planetoid Belt
1 1,000 km
2 2,000 km
3 3,000 km
4 4,000 km
...
For Atmosphere we have
Digit Description
0 No Atmosphere
1 0.001 Bar
2 0.01 Bar
3 0.05 Bar
4 0.1 Bar
5 0.2 Bar
6 0.3 Bar
7 0.4 Bar
8 0.5 Bar
9 0.75 Bar
10 1 Bar
11 1.25 Bar
12 1.5 Bar
13 2 Bar
14 3 Bar
15 4 Bar
16 5 Bar
17 10 Bar
18 50 Bar
19 75 bar
20 100 Bar

For Hydrographics we have
Digit Description
0 no water
1 5%
2 10%
3 15%
4 20%
...

For Population we have
Digit Description
0 0 to 5
1 5 to 24
2 25 to 124
3 125 to 624
4 625 to 3,124
5 3,125 to 15,624
6 15,625 to 78,124
7 78,125 to 390,624
8 390,625 to 1,953,124
9 1,953,125 to 9,765,624
10 9,765,625 to 48,828,124
11 48,828125 to 244,140,624
12 244,140,625 to 1,220,703,124
13 1,220,703,125 to 6,103,515,654
14 6,103,515,625 to 30,517,578,119
15 30,517,578,120 to 152,587,890,599
16 152,587,890,600 to 762,939,453,099
17 762,939,453,100 to 3,814,697,265,999
18 3,814,697,266,000 to 19,073,486,329,999
19 19,073,486,330,000 to 95,367,431,640,000
20 is read as 0

I'll have to think of additonal government types for d20

Law Level is just a DC

Tech Level is unchanged.

That's all for now.

 

[tjoneslo]

A few comments:

I'd reverse the scale for the starports (1 = X, 20=A).

For the atmosphere, don't forget you need to include the Taints. You could alternate the pressures with the same pressure + taint.

How do the modifiers between steps work? That is, the atmosphere value needs to be modified by the planet size. Suggestion: Use the Attribute scale from the PHB: i.e. size 10 = +0 atm. Size 16 = +3, size 8 = -1.

If you are looking for some more D20 based world building ideas, take a look at the Dragonstar Guide to the Galaxy. It has a planetary system generation system which has all of the same details as the T20 one, but with fewer steps and fewer numbers in the middle. It's more slanted toward building habitable worlds than the T20 system, but they're not claiming to generate every single world in the galaxy.

 

[TKalbfus]

A few comments:

I'd reverse the scale for the starports (1 = X, 20=A).

The Probability is the same, I just did that because in the original UPP generation system low results achieved higher quality starports.

For the atmosphere, don't forget you need to include the Taints. You could alternate the pressures with the same pressure + taint.

Atmospheric composition deserves a separate digit. You can have a 1 bar atmosphere that is not breathable. While the atmospheric components of a 0.001 bar atmosphere make little difference. Air pressure does determine whether oceans are possible however. We are focusing on planets that are of interest to humans. The mainworld is going to be the most habitable planet in the system, so I think we can bias it somewhat toward habitablity, because if it weren't, it wouldn't be the mainworld.

How do the modifiers between steps work? That is, the atmosphere value needs to be modified by the planet size. Suggestion: Use the Attribute scale from the PHB: i.e. size 10 = +0 atm. Size 16 = +3, size 8 = -1.

If you are looking for some more D20 based world building ideas, take a look at the Dragonstar Guide to the Galaxy. It has a planetary system generation system which has all of the same details as the T20 one, but with fewer steps and fewer numbers in the middle. It's more slanted toward building habitable worlds than the T20 system, but they're not claiming to generate every single world in the galaxy.

 

[TKalbfus]

Here is my complete main world generation system
First the Starport type:
D20
Result Starport
1 A
2 A
3 A
4 B
5 B
6 B
7 B
8 B
9 C
10 C
11 C
12 C
13 C
14 C
15 D
16 D
17 E
18 E
19 E
20 X

For size we go metric (km)
Digit Description
0 Asteroid/Planetoid Belt
1 1,000 km
2 2,000 km
3 3,000 km
4 4,000 km
5 5,000 km
6 6,000 km
7 7,000 km
8 8,000 km
9 9,000 km
10 10,000 km
11 11,000 km
12 12,000 km
13 13,000 km
14 14,000 km
15 15,000 km
16 16,000 km
17 17,000 km
18 18,000 km
19 19,000 km

For Atmosphere we have
Digit Description
0 No Atmosphere
1 0.001 Bar
2 0.01 Bar
3 0.05 Bar
4 0.1 Bar
5 0.2 Bar
6 0.3 Bar
7 0.4 Bar
8 0.5 Bar
9 0.75 Bar
10 1 Bar
11 1.25 Bar
12 1.5 Bar
13 2 Bar
14 3 Bar
15 4 Bar
16 5 Bar
17 10 Bar
18 50 Bar
19 75 bar
20 100 Bar

For Hydrographics we have
Digit Description
0 no water
1 5%
2 10%
3 15%
4 20%
5 25%
6 30%
7 35%
8 40%
9 45%
10 50%
11 55%
12 60%
13 65%
14 70%
15 75%
16 80%
17 85%
18 90%
19 95%
20 100%

For Population we have
Digit Description
0 0 to 5
1 5 to 24
2 25 to 124
3 125 to 624
4 625 to 3,124
5 3,125 to 15,624
6 15,625 to 78,124
7 78,125 to 390,624
8 390,625 to 1,953,124
9 1,953,125 to 9,765,624
10 9,765,625 to 48,828,124
11 48,828125 to 244,140,624
12 244,140,625 to 1,220,703,124
13 1,220,703,125 to 6,103,515,654
14 6,103,515,625 to 30,517,578,119
15 30,517,578,120 to 152,587,890,599
16 152,587,890,600 to 762,939,453,099
17 762,939,453,100 to 3,814,697,265,999
18 3,814,697,266,000 to 19,073,486,329,999
19 19,073,486,330,000 to 95,367,431,640,000
20 is read as 0

For Government we have
Digit Type
0 No Government
1 [Pop.]d20 tribes - roll 1d12+9 to determine type of each tribe/nation.
2 [Pop.]d12 tribes - roll 1d12+9 to determine type of each tribe/nation.
3 [Pop.]d20 nations - roll 1d12+9 to determine type of each tribe/nation.
4 [Pop.]d12 nations - roll 1d12+9 to determine type of each tribe/nation.
5 [Pop.]d10 nations - roll 1d12+9 to determine type of each tribe/nation.
6 [Pop.]d8 nations - roll 1d12+9 to determine type of each tribe/nation.
7 [Pop.]d6 nations - roll 1d12+9 to determine type of each tribe/nation.
8 [Pop.]d4 nations - roll 1d12+9 to determine type of each tribe/nation.
9 World Government - Company/Corporation
10 World Government - Participating Democracy
11 World Government - Self-Perpetuating Oligarchy
12 World Government - Representative Democracy
13 World Government - Feudal Technocracy
14 World Government - Captive Government
15 World Government - Council of Nations/tribes (roll 1d8 apply to this table)
16 World Government - Civil Service Bureaucracy
17 World Government - Impersonal Bureaucracy
18 World Government - Charismatic Dictator
19 World Government - Non-Charismatic Leader
20 World Government - Charismatic Oligarchy
21 World Government - Religious Dictatorship
22 World Government - Cyberocracy (Government by A.I. computer)

Law Level is unchanged

Tech Level is unchanged.

The way you roll up the New UPP is this way
Roll 1d20 for star port
Roll 1d20 for size (counting a 20 as a 0)
Roll 1d20-13 + size for Atmosphere
Roll 1d20-10 + Atmosphere for hydrographics
Roll 1d20 for population
Roll 1d20-10 + Population for government
Roll 1d10-10 + Government for law level (negative law levels default to 0)
Roll 3d6 for tech level and apply the following modifiers to it:
If Starport type B subtract 1 from tech level.
If Starport type C subtract 2 from tech level.
If Starport type D or less subtract 3 from tech level.

 

[flykiller]

For Population we have Digit Description
0 0 to 5
...
19 19,073,486,330,000 to 95,367,431,640,000

nineteen to ninety-five trillion? people? not much room for an ecosystem there - 'less animals are counted as citizens too....

 

[TKalbfus]

This is the fabled City-Planet of Sci Fi tradition such as Trantor or Corusant. People live in skyscrapers or underground in a globe girdling metropolis. There is not really an ecosystem here. The atmosphere has to be scrubbed and the food imported, providing a livelyhood for many agro-colonies and manufacturing planets to provide the needs of this massive population. Basically each digit represents a power of 5 instead of a power of 10.

 

[tjoneslo]

Originally posted by flykiller:
</font><blockquote>quote:</font><hr />For Population we have Digit Description
0 0 to 5
...
19 19,073,486,330,000 to 95,367,431,640,000

nineteen to ninety-five trillion? people? not much room for an ecosystem there - 'less animals are counted as citizens too.... </font>[/QUOTE]If you don't like that number of people, use a different log scale. Using 3.162^UPP gives a top value of 10 billion, the same as the standard Traveller system.

 

[TKalbfus]

I find that putting a cap on population at 15 (F) when rolling randomly helps, but I'g like to leave room for populations of 95 trillion if I want a city-planet. Having 1 in 20 as such a planet seems like too many to me. Likewise I'd cap law level at 20 (L), and tech level at 16 (G). Tech levels 17 and 18 aren't really defined well and are open to much interpretation. With these caps, you just treat all results higher than the cap as the maximum value allowed.

 

[robject]

Your system is internally consistent, and you yourself prefer to place limits on population rolls. All in all, a good job.

As far as really big populations go...

YMMV, but tens of billions is a pretty safe upper limit.

Considering the OTU has about 15 trillion people for all 11k planets, I'd say it's going to be very difficult feeding, say, 60 trillion people on one world. Imagine the supply lines coursing in from other systems -- necessities all. Imagine the agricultural requirements (would it make sense to build vast farms on asteroids at the Trojan points?). Now imagine the nightmare of planetary distribution... (shudder).

Imagine Texas, except instead of 30 million people, it has 300 billion. A bit over half the population of the Spinward Marches. That's the scale we're talking about... Dallas/Fort Worth would have 40 billion of those people! Better build arcologies. Really big ones.

Such a theoretical city would have ten times the transportation and distribution requirements (and problems) of our entire Earth! Can you say 'staggering'? (You might say 'crowded'!)

Now imagine 6 trillion WC's on the planet (1 per 10 people)... better handle waste on site; don't trust an interplanetary trucking company, 'cuz they might go on strike, and then... well... you are literally, literally in deep doo-doo.

The only way I can see how this will work is through a large world with very high technology. Higher than TL16, I'd guess. How 'bout a safe TL18.

However, such high tech in the Traveller world may also defeat the thing it's enabling: at TL16 we have gravitic cities. By TL18 those cities are essentially no different from really staggeringly huge starships, and thus can roam the insystem or indeed other systems. While they may be registered with the mainworld, they may be at any neighboring system at any particular week.

Suffice to say it might be difficult to justify so many people on one world. It's also very hard to come to grips with what a trillion people really means.

 

[far-trader]

Originally posted by robject:


<snip>

Suffice to say it might be difficult to justify so many people on one world. It's also very hard to come to grips with what a trillion people really means.

Indeed! In fact I've been trying to figure just how big a sphere (ship or planet) would be required for a population of 60 trillion based on just 4dT each (a stateroom).

I'm not sure about my numbers but I'm getting about 11,700km diameter (a bit bigger than an OTU UPP size 7 world). And that would be a total conversion of the planet to nothing except "staterooms" for the population, from the very core to the surface. Boggling.

 

[TKalbfus]

Just imagine 10,000 people every place you see 1 and you get an accurate picture. Now suppose the entire surface of an Earth-sized planet were as crowded as mid-town manhattan, what would the population of such aplanet be?

 

[far-trader]

Well a quick look at the US Census 2000 data for New York County (population about 1.5 million in 23 square miles) would give a population of about 3.8 trillion if applied to the total land area of earth. If we included the entire surface area of the earth it would be about 13.2 trillion. All assuming I did the math right

That's comfortable enough, given that there are places with much higher population density iirc. India and Japan leap to mind but I'd have to look that up to be sure.

So City Worlds are certainly possible in the low trillions or hundreds of billions at least, though with serious ecosystem/environmental issues. High TL should be able to handle that. Even just using clean fusion power would go a long way.

I'd look for a world with a good percentage of water (say 70% ) to use for intensive aquaculture to feed the land mass population and keep the water generally free for environmental balance.

 

[robject]

Good points + ideas, Dan. I'd also encourage large numbers of gravitic/orbital cities which can slowly cruise into orbit and back if necessary. Perhaps huge floating industrial complexes, too...

 

[far-trader]

Thanks robject. Just recalling some (I think) Arthur C. Clarke where his world city was all (or mostly) underground with automated land farming and forests above it. So you could keep the surface 'natural' and have the habitats mostly buried. That'd lower your energy needs and environmental impact significantly and provide more and varied food, reducing the strain on the aquatic side.

I like the idea of orbital to suborbital grav components, especially for things like the Starport. These would be naturals for vacation resorts too.

And not forgetting the floating/submarine communities in the oceans of course.

But this is starting to diverge from Tom's topic (though he did start us down this path ). Wasn't there some other thread on this before? If not we should start one so the topic can (in all probability ) die for lack of interest.

 

[TKalbfus]

Here are some examples showing my UWP, these represent real stars within 21 light years of Earth.

Trade Classifications: Ag: Agricultural, Ind: Industrial, WW: Water World, De: Desert World, Vac: Vacuum World,
Belt: Asteroid Belt, Ice: Ice Capped.

The ‘P’ in the PGB is in Traveller uni-digit code with values ranging from 0 to 24, these show the number of 25ths of the maximum population +1 that you add to the low end of the population range to get a more precise population estimate.

Coordinates (light years) Star Designation UWP Bases Trade PGB Stellar Data
(+00.0,+00.0,+00.0) Sol (Earth) ACAFE94-8 NS Ind 841 G2
(-01.6,-01.2,-03.8) Proxima Centauri B000CEA-4 N Ind, Belt 821 M5e
(-01.7,-01.4,-03.8) a Centauri; 128620 EA8EB30-D S Ag B11 G2
a Centauri; 128620 A200520-E N Vac Q10 K6
(-00.1,-05.9,+00.5) Barnard's Star; (+ 4° 3561) CFHAFKH-8 S Ind D20 M5
(-07.2,+02.1,+01.0) Wolf 359 B7EG4B6-D Ag 222 M8e
(-06.3,+01.7,+04.8) Lalande 21185; BD + 36° 2147 A9HLEA4-C N Ind, WW 400 M2
(-01.6,+08.2,-02.5) Sirius; 48915 CGKLF95-D Ind, WW M00 A1
Sirius; 48915 B742500-7 N L32 DA
(+07.7,+03.4,-02.8) Luyten 726-8 E8A95A2-7 Ag 700 M6e
UV Ceti BFBL810-7 Ag, WW Q10 M6e
(+01.8,-08.5,-03.8) Ross 154; AC-242833-183 B6769EL-3 S F11 M5e
(+07.4,-00.7,+07.1) Ross 248 CC43340-A S J10 M6e
(+06.4,+08.4,-01.8) E Eridani; 22049 C7EGD40-6 Ind 200 K2
(+09.7,-03.7,-02.9) Luyten 789-6 C400600-7 S Vac G00 M6
(-10.8,+00.7,+00.2) Ross 128 C210940-8 F00 M5
(+06.3,-06.1,+07.0) 61 Cygni; 201091 BBKLFC4-6 NS Ind, WW C10 K5
61 Cygni; 201092 E48H695-3 S Ag C00 K7
(+05.3,-03.0,-09.4) E Indi; 209100 AA3BBKL-E N Ice 121 K5
(-04.7,+10.3,+01.1) Procyon; 61421; a Canis A893300-D N N00 F5
Procyon; 61421; a Canis DGJJ7GM-4 G11 DF
(+01.1,-05.7,+09.9) + 59° 1915; 173739 CK93330-9 S G20 M4
+ 59° 1915; 173740 EF56CNJ-5 S Ind 910 M5
(+08.4,+00.5,+08.0) Groombridge34; BD +43°44; AB53AEG-D S 710 M2
Groombridge 34; BD + 43° 44; C421EJL-4 Ind, Ice P01 M4
(+09.2,-02.3,-06.9) Lacaille 9352; CD - 36° C7308F8-E 600 M2
(+10.3,+04.9,-03.3) T Ceti BJKL180-8 S WW 510 G8
(-04.4,+11.3,+01.1) Luyten BD + 5° 1668 CJGFBLB-8 S Ag M40 M4
(+11.4,+03.4,-03.8) L725-32; LET 118 B600ALJ-F S Vac A10 M5e
(+07.3,-06.4,-07.9) Lacaille 8760; CD - 39°; 202560 EGE78CJ-5 202 M1
(+01.9,+08.8,-09.0) Kapteyn's Star; - 45° 1841 EHKLFNL-6 S Ind, WW M10 M0
(+06.3,-02.7,+10.8) Kruger 50; 23!:J!:J50 A2129HL-9 N Ice 311 M4
DO Cephei; 239960 BKKDFDD-C NS Ind B42 M6
(-01.5,+13.0,-00.6) Ross 614 A9CFE50-E N Ind E11 M5e
Ross 614 BGKL2BE-7 S WW E32 M5e
(-05.0,-11.8,-02.8) BD - 12°4523 C400000-9 S Vac 911 M5
(+13.6,+02.8,+01.2) van Maanen's Star; Wolf 28 DG7BAFL-7 N13 DG
(-13.9,-01.9,+02.3) Wolf 424 A7DDFNL-D S Ind C40 M6e
Wolf 424 B99G000-8 N H00 M6e
(+14.3,+00.2,-02.0) G158-27 DF65FNG-9 Ind Q11 M
(+11.5,+00.1,-08.8) CD - 37° 15492 EHDG8E6-7 Ag M10 M3
(-08.6,+04.6,+11.4) Groombridge 1618; BD+50°1725 BDCH400-7 S Ag C50 K7
(-01.6,-10.2,-11.0) CD-46°11540 D3BG9BK-6 Ag 602 M4
(+07.9,-06.0,-11.5) CD-49°13515 B203D70-8 NS Ind, Vac, Ice 120 M3
(-01.3,-10.9,-10.7) CD-44°11909 BHBLBBE-B N Ag, WW 010 M5
(+13.1,+07.3,+03.4) Luyten 1159-16 C2618CL-9 S 330 M8
(-13.6,-06.6,+04.1) Lalande 25372; BD + 15° 2620; 119850 E100ADC-5 Vac A01 M2
(-00.6,-05.8,+14.7) BD + 68°946; AOe 17415-6 CKKL9F6-5 S Ag, WW K20 M3
(-06.8,+00.5,-14.3) Luyten 145-141; CC658 DACFFMF-3 S Ind 610 DA
(+14.6,-04.5,-04.0) Ross 780; BD-15°6290 D000FHL-C S Ind, Belt E20 M5
(+07.1,+14.1,-02.1) 40 Eridani; Omicron Eridani; 26965 AE87DNE-C NS Ind G00 K0
40 Eridani; - 7°781; 26976 DHGL200-A S Ag. WW A10 DA
40 Eridani; - 7°781; 26976 CF8E9HL-A S Ag J10 M4e
(-13.6,+06.6,+05.5) BD + 20°2465 DGJL360-1 WW 103 M4
(+07.4,-14.6,+02.5) Altair; 187642 BKC5F70-D S Ind P10 A7
(+00.2,-16.7,+00.7) 70 Ophiuchi; +2°3482 D691FNJ-4 S Ind A10 K1
70 Ophiuchi; 165341 DAH8F80-C S Ind 500 K6
(-03.2,+00.2,+16.5) AC+ 79°3888 CCKD300-3 S 120 M4
(+11.5,-03.9,+11.8) BD + 43°4305 BAGD460-F S Ag C10 M5e
(+03.5,+08.1,+14.6) Stein 2051; AC + 58 25001 CA20FBK-A Ind 450 M5
Stein 2051; AC + 58 25002 CKG7F80-3 S Ind J10 DC
(-12.2,+03.1,+12.1) + 44°2051 X600B50-7 Vac 540 M2
WX Ursa Majoris CCC6D70-C S Ind 902 M8
(-03.3,-15.5,-07.9) - 26° 12026; 155886 B691D60-9 Ind M10 K2
36 Ophiuchi; 155885 B5AK300-8 S Ag 940 K1
- 26° 12036; 156026 DJJL430-9 S WW 811 K6
(+07.9,-12.6,-10.9) - 36° 13940; HR 7703; A6DBFNE-B Ind P00 K3
- 36° 13940; 191408 X7BD7HH-7 Ag A10 M5
(+02.5,-05.9,+17.3) a Draconis; 185144 A9CLB9H-A Ag, WW K12 K0
(-07.8,+16.7,+01.2) Ross 882; YZ Canis Minoris CFELC40-6 S Ag, Ind, WW Q02 M4
(+03.8,-06.4,-17.0) Delta Pavonis; 190248 AB23140-A NS Ice F00 G6
(+18.6,-01.1,+00.7) 1° 4774 CHJL400-9 WW 433 M2
(+04.8,-12.3,-13.3) Luyten 347-14 DBB4780-B NS G30 M7
(-00.6,+17.3,-07.0) - 21° 1377; 42581 AKLE8D4-C C00 M1
(-03.4,+06.3,-17.5) Luyten 97-12 CC10510-A N P20 D
(-09.6,+15.0,-07.0) Luyten 674-15 BKKL5AA-9 N WW C20 M
(+10.1,+02.1,+16.2) n Cassiopeia; 4614 XG7DCDL-3 S Ind G01 G0
n Cassiopeia; 4614 AB974B8-B NS H12 M0
(-00.8,-10.3,-16.2) Luyten 205-128; UC 48 EBFE430-3 Ag Q10 M
(+02.6,+19.0,-01.2) - 3° 1123; HD 36395 E4A4FJL-C S Ind 811 M1
(-08.9,-11.5,-12.7) - 40° 9712 C9CL400-E Ag, WW 810 M4
(-04.3,+14.4,+12.0) Ross 986; AC + 38 23616 AKLL860-B N WW D10 M5
(+01.7,+18.9,+04.2) Ross 47; AC + 121800-213 DE30660-4 412 M6
(-03.6,+15.8,+10.7) Wolf 294; AC + 33 25644 BDLC210-A A50 M4
(+00.6,+19.5,-01.4) LP 658-2 BELLFF8-G N Ind, WW 300 DK
(-08.8,+07.9,+15.6) + 53° 1320; 79211 E140220-7 S De D50 M0
+ 53° 1321; 79210 XB00DD4-8 S Ind, Vac G00 M0
(+06.2,-18.5,+01.7) +4° 4048; 180617 D877640-5 130 M4
+ 4° 4048; VB10 D653610-A 811 M5
(+07.5,-11.8,-14.1) - 45° 13677; 191849 ABGLF9H-H N Ind, WW B10 M0
(+09.6,+11.2,-13.9) 82 Eridani; 20794 C850ENL-7 Ind, De E50 G5
(-05.8,-19.2,-02.9) Wolf 630; - 8° 4352 BE51FNL-8 S Ind 210 M4
Wolf 630; - 8° 4352 CA0AFGL-A Ind, Vac, Ice D20 M5
VB8 CC42BHE-A P12 M5
Wolf 629 BHLBCB5-A N Ind L31 M4
(-15.7,-12.3,-04.4) -11° 3759 C003C80-8 S Ind, Belt, Ice B50 M4
(+04.4,+00.4,-20.0) B Hydri; 2151 C609F80-5 S Ind, Vac, Ice 621 G1
(-03.1,-14.3,+15.0) + 45 2505; 155876 E8GGF80-5 S Ind F41 M3
+ 45 Fu46; 155876 CGKK7C5-7 S E00 M3
(+19.5,-03.4,+07.1) + 19° 5116 B500200-D Vac J01 M4
+ 19° 5116 BA20950-D S 610 M6

 

[TKalbfus]

The following describes another 6 digit cluster that more fully describes each planet.

The first digit describes the planet's gravity
Gravity. The planet's size digit is the number of times you roll a 3 sided die to determine the planet's gravity digit.

The second digit describes the planets's day length in hour ranges, and the third digit describes the number of hours within that range.

The 4th digit is the amount of oxygen in proportion to the rest of the gases in the atmosphere. The 5th and the 6th digits give the same description for Nitrogen and Carbon dioxide.

To get the percentages sum up the gas proportions indicated to get a total and divide each gas proportion by this total to get a percentage.

Here are the digit descriptions:
Digit Description (1 = Earth’s gravity)
0 0.00
1 0.08
2 0.16
3 0.23
4 0.30
5 0.33
6 0.36
7 0.38
8 0.40
9 0.43
10(A) 0.46
11(B) 0.48
12(C) 0.50
13(D) 0.53
14(E) 0.56
15(F) 0.58
16(G) 0.60
17(H) 0.63
18(I) 0.67
19(J) 0.70
20(K) 0.73
21(L) 0.77
22(M) 0.80
23(N) 0.85
24(O) 0.90
25(P) 0.95
26(Q) 1.00
27(R) 1.05
28(S) 1.10
29(T) 1.17
30(U) 1.25
31(V) 1.33
32(W) 1.42
33(X) 1.50
34(Y) 1.58
35(Z) 1.66

Day Length 1d20 (hour range) + 1d6-1 digit (hours; if 0 then the bottom of the range)
Digit Description
0 0 to 5 hours
1 6 to 11 hours
2 12 to 17 hours
3 18 to 23 hours
4 24 to 29 hours
5 30 to 35 hours
6 36 to 41 hours
7 42 to 47 hours
8 48 to 53 hours
9 54 to 59 hours
10(A) 60 to 65 hours
11(B) 66 to 71 hours
12(C) 72 to 77 hours
13(D) 78 to 83 hours
14(E) 84 to 89 hours
15(F) 90 to 95 hours
16(G) 96 to 101 hours
17(H) 102 to 107 hours
18(J) 108 to 113 hours
19(K) 114 to 119 hours


Oxygen 1d20-1
Digit Description (proportion)
0 0
1 2
2 4
3 6
4 8
5 10
6 12
7 14
8 16
9 18
10(A) 20
11(B) 22
12(C) 24
13(D) 26
14(E) 28
15(F) 30
16(G) 32
17(H) 34
18(J) 36
19(K) 38

Nitrogen 1d20-1
Digit Description (proportion)
0 0
1 5
2 10
3 15
4 20
5 25
6 30
7 35
8 40
9 45
10(A) 50
11(B) 55
12(C) 60
13(D) 65
14(E) 70
15(F) 75
16(G) 80
17(H) 85
18(J) 90
19(K) 95

Carbon Dioxide 1d20-1
Digit Description (proportion)
0 0.5
1 1.0
2 1.5
3 2.0
4 2.5
5 3.0
6 3.5
7 4.0
8 4.5
9 5.0
10(A) 5.5
11(B) 6.0
12(C) 7.0
13(D) 8.0
14(E) 9.0
15(F) 10
16(G) 20
17(H) 40
18(J) 60
19(K) 80

After rolling my custom UWP in the above postings the extention UWP is rolled this way:

Roll [size]d3 for gravity
Roll 1d20 for day length; 1d20-1 if size is zero.
Roll 1d6-1 for 10’s of minutes added to day length
Roll 1d20-1 for Oxygen proportion
Roll 1d20-1 for Nitrogen proportion
Roll 1d20-1 for Carbon dioxide proportion

This provides a more complete description of each planet