Simplifying Gurps Space world creation

[Agemegos]

Originally Posted by Fred Brackin

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.

Up until we started discovering exoplanets in 1992 the state of the art was Habitable Planets for Man (Stephen H. Dole, 1970). Dole's central estimate was 4.08 × 10^(-4) habitable planets per cubic parsec, which implies an average nearest-neighbour distance of 24 light-years for habitable planets. But of course not every habitable planet has a flourishing technological society on it.

[ericthered]

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).

Its a lot of rolling, but with the generator I've got its about 1 planet in 100. I think I just have a 50/50 chance of Garden vs Water.

[ericthered]

I've added a key!


also a way to control the random seeds used to generate the stars.


and started on dynamics: I don't have anything dependent on tides yet*, but I have axial tilt, years, months, and moon distances.


Next up is tidal-dependent stuff and society stuff.



*in the model the moons know who they orbit, but the planets don't know who orbit them.

Originally Posted by 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.

You use the browse button to select the file, and then use the load button. Yes, there was a bug in that before that only loaded the GUI but not the planet stats. Its fixed.



Right now we only store entire star sets. Storing individual systems does seem like a really good option though.

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.

yeah, I think I remember that... I'll have to figure that out at some point. Its not fixed yet.

The listing for the garden planet of the G8 star looked like this:
Note the flags "true false" at the beginning of the line for Ocean Coverage.

good catch. more marginal atmosphere trouble. Fixed.

I suggest listing ocean cover as a percentage.

good idea. done.

[Anthony]

Originally Posted by ericthered

Its a lot of rolling, but with the generator I've got its about 1 planet in 100. I think I just have a 50/50 chance of Garden vs Water.

Hm. It looks like my program for doing this is based on GURPS Traveller First In, not GURPS Space. GURPS Space is a lot more generous about interesting life.

[ericthered]

Originally Posted by Anthony

Hm. It looks like my program for doing this is based on GURPS Traveller First In, not GURPS Space. GURPS Space is a lot more generous about interesting life.

Gurps space is aggressive about putting a planet everywhere that bode's law says its possible, which means there is basically always something in the habitable zone. And if that planet is standard or large sized in the habitable zone, it always eventually becomes a garden planet, as long as the star doesn't blow up first. At about 7.5 billion years, every ocean planet is a garden planet and it can be as fast as immediately).



So yeah, its pretty generous.



*******************************************


Still working on getting the program finished. I think I got all of the days and years and tides and vulcanism and such finished. I'm still looking around for errors and squashing them and fixing misspelled sulfurs and such before I release again. Tidal forces were hard, because of the moon thing, and because space errata meant my source was wrong the first time I did them.

[David Johnston2]

Originally Posted by ericthered

Gurps space is aggressive about putting a planet everywhere that bode's law says its possible, which means there is basically always something in the habitable zone. And if that planet is standard or large sized in the habitable zone, it always eventually becomes a garden planet, as long as the star doesn't blow up first. At about 7.5 billion years, every ocean planet is a garden planet and it can be as fast as immediately).

No, there' s a cut off at +10 to the roll. Which means there's about a 40% chance that a standard or large ocean world will never develop native life before its star dies. Of course those worlds are probably pretty easy to terraform

[Anthony]

Originally Posted by ericthered

Gurps space is aggressive about putting a planet everywhere that bode's law says its possible, which means there is basically always something in the habitable zone.

Absent a gas giant migrating inward and ejecting everything else (which is apparently far more common than anyone realized before we had actual exoplanets to look at), that probably isn't all that unreasonable.

[Pursuivant]

Originally Posted by ericthered

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.

Further user-controlled parameters would be helpful:

Choice of metric/English measurements would be helpful for folks who use meters/C* vs. yards/F*.

Some method of flagging "systems of interest" in the "galaxy" graphic field. That would help in picking out and editing mineral rich or garden worlds and making itty dark-colored dots more obvious against a black field.

A grid pattern in the "galaxy" section to help give a better sense of distances between star systems.

White background/black grid for the galaxy section as a "printer friendly" option.

Possibly more work would be giving users control over "galaxy" or system generation parameters or switches, like minimum distance between star systems, chances of having a planet in a given orbit or habitable worlds, or excluding binary/multi-star systems (because they usually seriously reduce chances of garden worlds).

I'm not complaining, though! This is an amazing tool. Thank you for creating and sharing it!

[ericthered]

Originally Posted by David Johnston2

No, there' s a cut off at +10 to the roll. Which means there's about a 40% chance that a standard or large ocean world will never develop native life before its star dies. Of course those worlds are probably pretty easy to terraform

And the cutoff is different for Large Worlds, at +5. And Ocean worlds can have native life, just not photosynthetic.

And this is the sort of little detail I'm running around trying to fix right now: I've been using a 50/50 chance*. And I'm making sure you can edit all of the things you need to, and fixing when Hadean worlds have a black body factor of 100 times higher than they should and put fire back in Hades.

*this was originally built for just me, an I made a few choices I'm having to undo now. I think this is one of them. I might just leave my choice to replace tiny (ice) with tiny (hadean).

Originally Posted by Pursuivant

Choice of metric/English measurements would be helpful for folks who use meters/C* vs. yards/F*.

I think this difference only shows up once: every thing else is in reference to native values of the earth and sun. I could just add C in parenthesis. Any other values you've noticed that would benefit from metric?

Some method of flagging "systems of interest" in the "galaxy" graphic field. That would help in picking out and editing mineral rich or garden worlds and making itty dark-colored dots more obvious against a black field.

That's a good thought. Garden worlds already have a green dot just underneath them. I'm looking into creating a system browser that's not a sector map.

A grid pattern in the "galaxy" section to help give a better sense of distances between star systems.

That's interesting... Yeah.

White background/black grid for the galaxy section as a "printer friendly" option.

That's also a good idea. I hadn't thought about printing.

Possibly more work would be giving users control over "galaxy" or system generation parameters or switches, like minimum distance between star systems, chances of having a planet in a given orbit or habitable worlds, or excluding binary/multi-star systems (because they usually seriously reduce chances of garden worlds).

Yeah, that's more work. Some of its easy, and some of it would be really hard. I'm looking into adding at least some things you can set before generating.

I'm not complaining, though! This is an amazing tool. Thank you for creating and sharing it!

I glad you like it. I asked for feedback, and you have delivered.

[ericthered]

Wow, its been a while, and I've been working on this. Right now the version I have has societal stats up to control rating, better formatting, better saving, correct garden world generation, better automatic naming, more consistent editing, a list of systems that can be sorted by star size, resources, habitability, and affinity, and the ability to save specific systems, load specific systems, and generate fewer systems.

Its not live yet because I'm trying to iron out the bugs before I give it to you.

A few things about the society generation bug me:

• When time-spans are short, outposts have larger populations than colonies, because outpost populations are time invariant.
• If there are two very desirable planets in a system and they are out of reach of each other, only one will be colonized. I know I can override this, and its probably expected that GM's will, but when coding its something I have to override. The big case here is two habitable planets each on a binary star
• Every single system is colonized, even if its just resource 0 tiny rocks.

One interesting thing I've noticed is that sulfur moons get a lot of colonies, because they tend to be very volcanic and thus have high resource numbers.

Also, the files are a bit bigger than I expected: 1400kb to save 100 systems.

I hope I can get this new version to you folks soon!