Simplifying Gurps Space world creation

[ericthered]

Originally Posted by Agemegos

Did anyone complete a proper instance of the GURPS Space (4th edition) star system and planet generation sequence?

Depends on what you mean by proper. I've got a web-based version I've basically never shared. It has a very simple visual representation of the system. As far as generation goes, I think its complete. The editing functionality is incomplete (The big things missing are the ability to add and delete stars, planets, and moons, and the ability to change marginal atmosphere tags), and there is no real ability to save. It also is very unfriendly to touch screens.


But if you want something that will generate a hundred systems at the click of a button... Here it is.

[Agemegos]

Originally Posted by ericthered

Depends on what you mean by proper. I've got a web-based version I've basically never shared. It has a very simple visual representation of the system. As far as generation goes, I think its complete. The editing functionality is incomplete (The big things missing are the ability to add and delete stars, planets, and moons, and the ability to change marginal atmosphere tags), and there is no real ability to save. It also is very unfriendly to touch screens.


But if you want something that will generate a hundred systems at the click of a button... Here it is.

Thanks! I’ll check it out when I get to a computer with a mouse and keyboard rather than this iPad. Does it do the “Basic” sequence (i.e. start with surface conditions of one world and work upward and outward?

[ericthered]

Ok, I just updated it. Now it works with touchscreens, can add and delete planets and moons, can save and load onto files on your computer, draws asteroids better, and has editable names for stars, planets, and moons (Systems still aren't nameable).

I still need to allow editing of the atmospheric tags and naming of systems. A mode that lists systems instead of showing them in a map would be nice as well, the ability to generate new systems with a seed, and it could all use some styling.

Originally Posted by Agemegos

Thanks! I’ll check it out when I get to a computer with a mouse and keyboard rather than this iPad. Does it do the “Basic” sequence (i.e. start with surface conditions of one world and work upward and outward?

No, this starts with systems, works out stars from there, and planets from there. It very much uses the "Advanced" system... but you can change the values of an existing planet, and nudge the entire orbital system back and forth, so I don't think it matters much.


Let me know what I can do to improve it.

[Agemegos]

Originally Posted by ericthered

No, this starts with systems, works out stars from there, and planets from there. It very much uses the "Advanced" system... but you can change the values of an existing planet, and nudge the entire orbital system back and forth, so I don't think it matters much.

Understood. I did both Basic and Advanced, but I use Advanced far more.

Let me know what I can do to improve it.

So far I have only had time for a quick first glance, and have only administrative stuff to suggest.

I think it needs better labelling: a page header, captions or titles on the sector map, star system diagram, planet-and-moons diagram…. It took me a little while to work out how to select a moon. Speaking of selecting a moon, when I have a moon selected for display there is no indication of what I have selected.

I think it needs a key to the colour codes used for spectral class in the map and planet types in system diagram. Also to the meanings of the lines in the system diagram indicating orbital limits, the life zone, and the snow line, and of the diagonal lines indicating companion stars. I was momentarily puzzled that there were some coloured disks that I could not click to select (I mistook an M7 companion star at the left of its row for some sort of planet).

There are a few places in the Star and Planet tables where figures are given with far too many digits. Stellar age, star radius, and planetary gravity and diameter ought to be rounded to three or even two significant figures, temperatures ought to be rounded to the nearest whole degree. Except maybe in editing mode.

I think you ought to indicate the units for numerical figures: M☉, L☉, Ga or Gyr, whatever unit stellar radiuses are calculated in, C or °F (I am genuinely in doubt which is in use), bar or kPa, g♁ or m/s² or ft/sec², D♁ or km or mi., ρ♁ or g/cc², as appropriate.

You report a few values that are calculated as part of the generation procedure but that have no physical existence that would be apparent in the game universe or that would be abstruse astronomical values not directly apparent to an observer. That is, the "Limits" value of a star, and the blackbody temperature atmosphereic mass, and Size values of a planet. In fact, I'm not super sure what the Orbit value of a star and the size value of a planet are. I'd suppress those except in editing mode.

I would recommend reporting the full planet type, e.g. "Standard Garden" rather than just "Garden". If you don't want to do that, I think you need to add a description of the main components of the atmosphere. Because I need a better way of knowing whether a planet is Large Garden (with helium in the air) or Standard Garden (without helium).

In one system I got a Garden planet with an entry that said "Air Quality: true", and I don't know what it means.

I see that you have gone as far determining RVM and calculating Affinity. To go further in that direction, to carrying capacity, population, wealth, economic value, society type, CV etc. depends on campaign specifics such as the TL and Settlement Type. That means getting user input, which might be a pain. But it does let you add a lot of value, because population, economic value and so on are figures that a GM needs and are tedious routine to calculate.

I see that you have not done year length, month lengths, tidal heights and periods, day lengths etc. Nor tectonics and volcanic activity. Nor orbital eccentricity and rotational obliquity ("axial tilt"). Do you plan to?

There are some values that the GURPS Space (4th edition) star system and planet generation sequences don't calculate, but that are easy to calculate or estimate from figures that they do generate, and that are useful to GMs or conspicuous to the characters in the setting. These include the brightness of sunshine on a planet or moon, escape velocity of a planet, the scale height of the atmosphere, the altitude of the Kármán line ("edge of space"), the period of low orbit, the boiling point of water at sea level, the land area, the population density, the apparent size of the sun and moon (and primary planet, for moons), the periods and ranges of the main components of the tides. I added some of those as Easter eggs. Do you want to consider any of them?

[ericthered]

Thats great feedback. Lets see what I can do:

Significant figures on view-mode numbers --- that's easy. Done.

I've added a selection indication for the moons. And a subtler one for the stars. Not sure the best way to tell people to click on the moons.

Labels on all of the measurements -- good idea. Temperature is in F. I had to use "Of Earth" and "Of Sun" in a number of places.

It hadn't occurred to me that black-body wasn't useful at the end, but you're right, its only critical during generation. I've hid a lot of that. "Orbit" is actually "Distance from whatever its orbiting around", which is an important value... but should be better labeled.

I've gone your way with reporting size (that is, a word at the start of the type line). I call it your way, its really the book's way, and its probably what people expect to see. The size shows up for editing, mostly because making a proper dropdown takes time and I'm doing the quick stuff first.

"Air Quality:true" means "This world has a Marginal Atmosphere". I've changed it to more clear.

I think it needs a key

That's a good idea. haven't done it yet, but its next on the list.

captions or titles on the sector map, star system diagram, planet-and-moons diagram

Yeah, that's harder than it should be. You're right, it's just an effort at this point.

carrying capacity, population, wealth, economic value, society type, CV

That's something I could look into doing. Getting the Tech level isn't hard. Society type I can actually make either globally or locally editable, and then save the dice roll.

Trade routes would be a bit harder.

I see that you have not done year length, month lengths, tidal heights and periods, day lengths etc. Nor tectonics and volcanic activity. Nor orbital eccentricity and rotational obliquity ("axial tilt"). Do you plan to?

Thanks for the reminder about those. Not up yet.

There are some values that the GURPS Space (4th edition) star system and planet generation sequences don't calculate, but that are easy to calculate or estimate from figures that they do generate, and that are useful to GMs or conspicuous to the characters in the setting

Yes.

[Anthony]

I wrote some programs to do this a very long time ago (which don't seem to run any more) but as I recall the problem you run into is that you need to roll up an absolutely ridiculous number of planets before you produce anything interesting (the rate of simple+ life is less than 1/1,000).

[Agemegos]

Originally Posted by Anthony

I wrote some programs to do this a very long time ago (which don't seem to run any more) but as I recall the problem you run into is that you need to roll up an absolutely ridiculous number of planets before you produce anything interesting (the rate of simple+ life is less than 1/1,000).

I had a similar experience, which was a big part of my motive to get a computer to do it. In my Excel-based generator I used data tables to generate systems in batches of ten thousand or so, and eventually made a version that used star catalogue data instead of randomly generating stars, and then generated universes in batches of a thousand each with ten thousand stars. (The setting I use is universe number 169.)

If you don't want to generate a plethora of stars, pick the suitable ones, and then go there, then the thing to do is to use the Basic generation sequence and not the Advanced one.

[Fred Brackin]

Originally Posted by Anthony

I wrote some programs to do this a very long time ago (which don't seem to run any more) but as I recall the problem you run into is that you need to roll up an absolutely ridiculous number of planets before you produce anything interesting ).

Back for Space 1e I took a cube of space 216 parsecs on a side and hand-calculated how many results of each kind you got. That's starting off with more than 10 million rolls just to see if there's a star in each 1 parsec cube.

I don't remember everything but aside from some oddities like 400 habitable moons of GGs the headline was an Earth-like world every 100 parsecs. This reinforced my desire to throw rocks at Traveller's 1 parsec/week Jump drive.

A conversation with Agamegos a year or two ago moved that figure up to 200 parsecs between Earth-like worlds.

Interestingly, when I looked at Gurps Humanx again a few years ago this book that predates Space 1e (the TL scale stopped at 9) had hundreds of parsecs between major Commonwealth worlds and their KK Drive was proportionately fast. Some impressive homework from Alan Dean Foster unless he selected the scale at random.

[Anthony]

Originally Posted by Fred Brackin

Back for Space 1e I took a cube of space 216 parsecs on a side and hand-calculated how many results of each kind you got. That's starting off with more than 10 million rolls just to see if there's a star in each 1 parsec cube.

I remember designing an inverted world design system (start with the assumption of something interesting, back-generate for what's likely to produce that), but I can't find it at the moment and it might have been more inspired by than actually based on GURPS Space.

[Agemegos]

Noodling around through random output I came across a gorgeous system, a G8/K6 binary with a standard garden world orbiting each star, a strong terraformation candidate (Ocean world) orbiting one of them, and some circumbinary planets. Lovely! I saved it and got a .json file that I don't quite see how to open.

The outermost planet of this system is a "Tiny Sulfer" (sic) planet. Apart from the typo, I seem to remember that sulfur worlds ought to appear only as the innermost moons of gas giants.

The listing for the garden planet of the G8 star looked like this:

name: 7rw-I4
type: Standard Garden
temperature: 122 F
climate: Hot
pressure: Standard (0.907 atm)
gravity: 0.667 G's
blackbody: 301.4 K
toxicity:
tags: Breathable Organic Toxins
true false Ocean Coverage: 0.7
affinity: 6
resource Value: 1
diameter: 0.741 of Earth
density: 0.9 of Earth
distance from star: 0.648 AU
minor moons: 0
major moons: 0

Note the flags "true false" at the beginning of the line for Ocean Coverage.

I suggest listing ocean cover as a percentage.