[Space] System Generator
 

A friend and I were thinking about writing some code to automate the process of randomly creating a star system, as outlined in 4ed Space. I was looking at the .pdf with the planetary control sheet, and basically the idea is to try to make a program that has a bunch of fields on that .pdf, you enter what you want (e.g. Primary Star solar mass = 1.1 or garden world in system) and the program back engineers the rest just like you would do if you were doing the stuff on paper. Or you can just hit the random button and it does the whole thing for you.

What I was wondering was this.

1) Whats the legality of this? It involves a couple of copyrighted materials (GURPS Space 4th ed and the GM Planetary control sheet PDF.) Do I just have to put in some disclaimers, give credit, etc? Or it it verbotten, since it automates the process of two chapters of GURPS Space? If thats the case, what if I distributed it in a zipped file whose passcode to unlock it was the nth word of the kth page of GURPS space (or something equivalent)? I don't plan on selling this or anything, just figured if I'm gonna put in all the time and effort others should have the opportunity to enjoy the fruits of my labor.

2) Has something like this already been done?

Thanks in advance for your responses.

Re: [Space] System Generator
 

I'm almost positive that you are allowed to make this provided that you do not sell it and put a notice (" GURPS is proporty of Steve Jackson Games Inc...") somewhere in the program.

Re: [Space] System Generator
 

I would LOVE to see a 4th ed. system generating program built.
I would buy that hypothetical program without a moment's hesitation, if it weren't illegal for you to sell, that is.

Re: [Space] System Generator
 

I wonder if you could submit a proposal for the program to e23?

Re: [Space] System Generator
 

Read this first:

http://www.sjgames.com/general/online_policy.html

I believe this is the relevant part:

V. So, does that mean that I can . . .
Create a character generator or other game aid?
Yes, as long as you include the appropriate notices. We want to ENCOURAGE our fans to create these programs, share them with the community, and have fun doing it. If you want to charge money for a game aid based on our work, the Online Policy does NOT apply . . . you must either get a license from us, or sell us the game aid for distribution as a regular product, and either way we'll hold you to professional standards. Email licensing@sjgames.com with a formal proposal letter.

We do, however, have some advice for creators of game aid programs. First, provide documentation. Some simple instructions on how to use the most basic features will be a big help to users. Second, support your creation. We've set up a forum for feedback; plan on being aware and active in these discussions.

Re: [Space] System Generator
 

hope you guys use XML as a database.

Re: [Space] System Generator
 

Agemogos,

I was talking about the entry of the constants you want for the system, as far as using the whole .pdf. Once you hit the randomize button, the hope was to print out the relevant information on the Planetary Record sheet(the second to last page in the .pdf) It's one page, has world/system info, and seems fairly well summarized. Even has a hex map for where certain land features might be, although I think that would be up to the individual GM to fill in.

The only problem with it is if you have multiple colonies within a single system, you would need to make a separate sheet for each colony as regards to it's economic/etc info, as all there is room for right now is colony data on one colony. I don't think it's unreasonable to presume that most systems will have one major economic/political center, and if a system has multiple ones, you can always just copy over the system info to a new sheet, focusing on a different colony per sheet. If you need more data because your players are going to be spending a whole lot of time in one system, well then you probably won't be doing random generation and will probably want more detailed notes for it anyways(I wouldn't try to run a THS campaign off of planetary record sheets, even with one record sheet per planet, for example.)

An index page and batch mode may be beyond the scope of the project, (unless e23 starts paying me, that is, but I'll need to put some serious thought into how much time/effort I can afford to put into this, as I'm heading into my Junior year of mechanical engineering this fall.) But, I'll see how much extra work it would be once I actually get started. No promises.

Thanks for the responses, and I'll try to post regular updates about the status of the project. Or at the very least let you know when it's finished.

Re: [Space] System Generator
 

Out of curiosity, what do you propose then? From what I've seen from GCS, Java doesn't look good for generator-type programs. I also envision the horror of having to compile the generator from a C source. Anything more esoteric than that will probably compromise cross-system portability.

Re: [Space] System Generator
 

Oh. Missed that. Somehow I never learned how to save forms through HTML. In fact, I'm always annoyed when my browser, upon closure, forgets a half-finished reply I was writing to the fora. That's why I always open up vi to write down any ideas.

Re: [Space] System Generator
 

I'd do it in html, javascript and xml (if required). Absolutely no worries about cross-platform compatibility - you just open it up in your browser.

Create the input form in html, where the user enters all the relevant data, and hits the Calculate! button. You could even enter only partial data, in which case after hitting Calculate! the program detects which input fields were left blank, fills them in randomly, and does the calcs. The output comes out in plain text, html or xml, depending on the user's choice.

Batch mode. Not hard to do, it's standard string processing. The user gives input in plain-text form (since it's the fastest to write up), with the list of all required data in a specified format (pipe delimited, tab delimited, whatever), and the program reads it and processes it in the same way as for a single system. Creates output in plain text, xml, single-page html or cross-linked multi-page html.

Since this thing is an automotion of a tedious task, you have to go for maximum funcitonality. It's a bit more work then just writing a simple script for single system generation with all the parameters supplied. The program should detect what is missing, and give the user a multitude of options for control over output format and other stuff, etc etc.

Re: [Space] System Generator
 

I wrote a character generator for Rifts by using XML for each character database and automating MSIE for the screens. I used XSL files to take XML and then produce datascreens and for exports. it was my first attempt at XML/XSL and while it looks clunky now, it works and was decent for my first shot at it.

automating MSIE allowed me to do things like have clickable columns in HTML display tables, such that if I needed to "add all first level spells" I could double-click the column header and the program would add everything. Same with deleting, as it saved having to make 30 or 40+ clicks just to add or delete a group of items. HTML tables also allow you to disable portions like if a certain skill or power isn't available you can disable that particular item (or entire column) and work from there. You can pickup COM objects that do this, but then they have to be installed, etc, which may or may not be a pain.

HTML also allows dynamic sizing of DIVs and placing and hiding things very easily. CSS allows easy formatting.

The other thing was that at certain points, I had what amounted to a spreadsheet displayed on screen as it had 30+ rows, and 15 columns (representing each level) and a certain row (say saving throw vs Horror Factor) gets a 1 at 1st level, 1 at 5th level and 1 and 9th level and so on. This way you could enter a particular item freehand "Save vs Little Green Men" and then enter the bonuses as needed. Then the script would grab the HTML from the display, I'd run it thru HTMLTidy, turn it into XML and then query the 300+ inputs very quickly, to update the character database. Turning HTML into XML means you can do some impressive things, like only grab rows that don't contain all zeroes and not have to bother with inventoring each and every one every single time. HTMLTidy is a single DLL and my scripts could peek at the registry, tell if it wasn't already installed, to use regsvr32 and register it silently and then proceed to use it, all transparent to the user.

Sorry I could go on for hours. Anyway, MSIE is on most windows PC, and even if your user doesn't use it, you're only using it locally, not for Web-use and you can reap all the nice font and display uses from it. DHTML is pretty simple.

Re: [Space] System Generator
 

I plan on having the program generate the entire system, including moons of all planets, including gas giant moons and ring systems, as well as asteroid belts. I also intend on giving the user the ability to toggle on/off certain aspects, such as brown dwarf stars and artifacts.

You bring up a good point about PDFs. I'll have to give it some thought, but an easily editable output format would probably be best.

Re: [Space] System Generator
 

make sure you look this post over thoroughly

Web-based Automatic Sector Data / Map pdf Generator

while you might not be interested in the Traveller aspects, the author/coder has done an awesome job with the project. I think it's for Mac, but she might have some Windows insights for you.

Re: [Space] System Generator
 

There is a script for astro synthesis 2. It added typical gurps statistics to world description (like TL etc.)

Re: [Space] System Generator
 

I read this thread last week, weeks after I started writing my own generator for star systems based on the GURPS Space rules.

Thanks for the wonderful ideas. And especially to Exxar. I was writing it in an obscure scripting language, but I've started learning JavaScript since it looks like it can do everything I need and is much more portable.

Not meaning to hijack your thread or anything. But once I've got stuff that I've done so far converted to Javascript, I can post it here for you or anyone to use. And if you happen to know the arcane scripting language of awk, I can post what I have done already. It's looking good so far, but still far to go. But I'll probably have to write a java applet or something to do the graphing of the orbits that I want to do.

Plus, knowing me, I'll probably add inclination of orbits as well. Many of you guys sound like you know way more about the star system mechanics than I do. So, I'll check back periodically for ideas and answers.

If I should have started a new thread for this, please be kind and just let me know. I've never used forums much so any unpoliteness on my part just means I'm ignorant of etiquette.

Tulonsae

Re: [Space] System Generator
 

I can't even tell you all how excited I am that a utility like this could be out. Mmm mmm goood!

Re: [Space] System Generator
 

No kidding. I wrote a bunch of AppleScripts that access various AppleWorks spreadsheets. They will, in fact, generate complete random star systems. Infortunately, I'm sure they're of good to no one but GURPS players with G3 Macs--that is to say, me. :)

Are you sure you'll be able to provide us the finished product when you're done?

Re: [Space] System Generator
 

Tulonsae: I don't mind at all, I figure if it's all in one place it's easier for everyone, right?

You sound like you're much further along than me. Thats not very hard, as I'm in the middle of midterms, so progress has slowed considerably.

My only real comment is that most planets are going to be pretty much in the plane of the elliptical. Anything with a highly eccentric(or significantly out of plane) orbit is much more likely to be an Oort Cloud/Kuiper Belt Object (like Pluto,) with the exception of any asteroid belts, as they'll tend to be much more scattered. Also, although it's not mentioned in any of the system generation tables(I think) asteroid distribution is gonna be a bit wonky(If you're actually concerned with where the asteroids are in the belt, as opposed to there just being a belt) due to the gravitational effects of any gas giants in the system. Basically there's huge holes in the belts due to certain parts of an orbit being more stable than others. Also, said gas giants are likely to have clumps of asteroids in their L4 and L5 orbits(60 degrees forward of the gas giants orbit and 60 degrees behind the orbit.)

I digress. I'm an asteroid geek. Anywho, like I said, not very likely that most planets will have highly eccentric orbits, but anything is possible. Look forward to seeing what you come up with.

Re: [Space] System Generator
 

It seems natural to me that planets with high eccentricities will likely have high inclinations. My reasoning is that circular low-inclination orbits are normal, and perturbations might change the eccentricity and inclination, but not just one or the other. To that end I plotted the inclination and eccentricity data for our solar system. For lack of anything better, I choose a linear fit to the data and determined that for a planet in our solar system, the

Inclination (in degrees) = 50.274 * Eccentricity with an R-squared value of 0.7519 when you include Pluto
or
Inclination (in degrees) = 31.621 * Eccentricity with an R-squared value of 0.5629 when you don't include Pluto.

If you're really serious about adding inclination data, let me know and I'll be happy to work with you on it. (I have an M.S. in Astronomy.)

Re: [Space] System Generator
 

I'm another GURPS player with a G4 Mac. (Woot!)

Re: [Space] System Generator
 

Cool, guys. Thanks a lot.

I'm working on getting my current work into JavaScript now. It'll probably take a few more days. But at least I'm getting the basics down (JavaScript, that is). So, that should be portable.

And I'll warn you now. I'm going to concentrate on getting the code working rather than how it looks - at least at first. I'm absolutely sure that people here can help me with how the UI should really work.

I think it would be great if we can use each other's work...

And, I'm only up to generating the stars and their orbits. Once I get this into JavaScript, I'll start on the planetary orbits.

But a lot of the comments here have given me good ideas about the interface. I suspect, though, that someone here will end up making in more user friendly. I'm more of a backend person.

thanks,
Tulonsae

Re: [Space] System Generator
 

And, yes, I'm really serious about adding inclination of orbit.

thanks for the offer.
I'll take you up on it.

Tulonsae

Re: [Space] System Generator
 

Yep, I did this too, except I used AppleWorks spreadsheets. Some advice I might offer.

1. Generate all random numbers in the top 10 rows above the general area where they will be used. Then you can simply cut and paste values on those rows when you're done to keep any values from accidentally changing later.

2. Think about each chart the book uses for pulling random values. Often, it's easy enough to see they're using a formula, but presented it as a chart to make it easier for people that are afraid of equations. If you can figure out what equation they used to make the chart, you can use that equation in your spreadsheet.

3. Break it up into a few spreadsheets. E.g. One to generate the starts. One to generate the planets around the star. One to generate the planet info.

Re: [Space] System Generator
 

How did you handle calculating planetary rotation periods, which I assume are part of the celestial mechanics, as you need to know about the moons first, which I assume are part of the physical properties of planets and moons?

Re: [Space] System Generator
 

This sounds great!

Where is your worksheet posted?

I'm still working on mine, of course.

Tulonsae

Re: [Space] System Generator
 

I did an Excel Sheet using VBA back when Space was published.
If you are interested PM me.

Re: [Space] System Generator
 

Don't forget longitude of perihelion and longitude of ascending node. Some of us are a little psycho and calculate true anomaly and distance over time.

G4 laptop, G5 desktop. Want a Mac Pro so I can run leveller, l3dt and wilbur on WINE. Woot!

Re: [Space] System Generator
 

That's great.

I haven't worked with real phyics equations for over 20 years. And I still have that physics book and the stuff I did somewhere... I had worked out the 2-body stuff, orbits, and things. But I could never find the info on the multi-body equations...

And, of course, things have changed since then, anyway. So, I appreciate any help or corrections that I can get for what I'm working on now.

I'm further behind than I thought I would be. Learning a new scripting language always takes some time... And, of course, I got distracted by working on my website in some other areas.

But if there are any Unix geeks out there, I'd love to post my existing awk script so someone could review it and point out any calculation or assumption problems.

In the meantime, I'll keep looking for everyone else's work, and post mine as soon as I have something portable (i.e., for non-Unix geeks). Even if it's only a few of the calculations.

Tulonsae

Re: [Space] System Generator
 

And one more thing. Of course, I don't intend to put this out commercially since it's based on GURPS stuff so I'm going to put this into Public Domain (as opposed to any of the license stuff that people use nowadays).

So, anything I post for the space system generator is ok to use, but you have to follow the Steve Jackson Games license and copyright rules for anything dervied from their stuff.

Tulonsae

Re: [Space] System Generator
 

Agemegos, if there's such a thing as a roleplaying, space savvy, spreadsheet making, ninja, samurai, cowboy, secret agent, mega-pimp, then you are it. Thanks for the work on this and I can hardly wait to see the results!

Re: [Space] System Generator
 

The 4th ed. Planetary Record Sheet displays the following: Planet #, Name, Orbital Radius, Type, Diameter, Density, Gravity, Atmosphere, and Notes all on one row for each planet in a system. You might start with that just to be consistent with SJGames. You could then add other options. E.g. my spreadsheet gives the Star Trek class of the planet--Earth is M class.

I'd mention it in the "Notes" column if it's more than 0.1.

Agreed. I'm surprised this isn't in the official 4th ed. Planetary Record Sheet, but "Density" is. (Agreed, get rid of "Density".)

More useful, but not cooler. Use miles or km. (You and you players will have Earth's diameter memorized in no time and will enjoy looking at a Galactic Survey Report that has real life units and understand what they're looking at.

Agreed. The trick is including this and still have all the data fit on one row. I opted for listing the primary constituents and the pressure category. E.g. N2, CO2, dense.

I think you'll find they're not. Most planets will have 0%. Any planet that isn't 0% will likely be interesting enough to have it's own record sheet and you can provide that information there. In practice, most systems will have only one (if that) planet worthy of a proper Planetary Record Sheet. In my game, a typical Galactic Survey Report gives all the info for the most habitable planet (which would include Hydrographic coverage) and then the row-by-row list of info for all the other bodies in the system (which usually all have 0% Hydrographic percentage anyway).

It's not on the 4th ed. Planetary Record Sheet; but I agree, and it's something I added to my read-outs.

I know you're aware, the errata for GURPS: Space is woefully incomplete. Others who are reading this thread should be aware of a better list of GURPS: Space errata

Since these are simple numbers, you might adopt a convention like H(R,A)

You might include it in a "Notes" column for any Axial Tilt greater than 45%.

Ah, I love colour-coding.

If you want my conditions for converting GURPS stats to Star Trek (actually, PRIME DIRECTIVE) planetary classes, let me know. (It will take me a few weeks to get them to you as I'm on holiday right now.)

Re: [Space] System Generator
 

Overall it looks pretty good. It does seem to be printing the number of moonlets twice though. Also, if there's a spot to squeeze in rotational period so we know how long a day/year is, that'd be cool as well. Otherwise, looks good. Oh, is the size in earths?

Re: [Space] System Generator
 

No, just include the units in the top row like you did for temperature: temp (C).

Re: [Space] System Generator
 

I caved and went with a landscape layout. I don't see any way around this if you decide to add further info. More of my suggestions follow.

As far as the stellar data goes, nobody says gigayears; use 10^9 years or billion years. Of course, if computer geeks took over and formed a meritocracy, then stay with gigayears. :) Also, "K4 V" is how a stellar class is usually given, as opposed to writing out "K4 main sequence"; but this deviation from the norm is not an egregious as using the prefix "giga".

The mass and class of the companion star did not get printed. Also, the units for the periapsis and apapsis aren't given. Btw, I like the idea of giving periapsis and apapsis as opposed to the semi-major axis and eccentricity for the stellar companions.

The first column(s) should give the planet number and/or name. E.g. 3, Earth or Sol 3.

Consider using things like "N2, O2" or "CO2" instead of "breathable" or "suffocating". I think your planetologist PC will enjoy looking at a Survey report, seeing a more raw from of the data, and coming to the conclusion him/herself that the atmosphere of the 2nd planet is probably breathable.

Unless hydrocarbon oceans are of importance to your campaign, the hydrographics column could be done away with. As I said, most people really only care about surface water, and any planet that has significant surface water will be worth a dedicated planetary recordsheet anyway. For the quick survey list of all the system bodies, the world type, Habitability Index, and colour coding are plenty enough to decide what planets are worth a more detailed look.

I see you didn't include the length of a day or year. People seem to want to know that, but I'm thinking now it's only important if they intend to land on the planet; in which case they'll want the full Planetary Record Sheet for that planet anyway. So now I'm thinking leave it off, especially since you're already including the interesting case of tidelocked on the system overview.

Consider at least adding the RVM to the Habitability Index. Something like HI(RVM) wouldn't take up much for space, and is at least as important as knowing what the liquid hydrocarbon coverage is.

Agemegos, this looks great!

Re: [Space] System Generator
 

I don't like the sizes being in earth units. If that's just me, don't change it; as I have to admit, having them in earth units does make the data table nice and tidy.

Re: [Space] System Generator
 

I've seen gigayears (Gy) in a number of places, including scientific texts and rpg products. I'd say it's less geeky than using the 'Y x 10^9' notation, which only seems non-geeky if you're a maths geek or engineer. :)

I think it's more, not less, egregious. It's also a space-waster.

Re: [Space] System Generator
 

Most defintely would be welcome. You are aware, however, that you can do this with a formula? Makes the sheet's disk usage a little higher if you have to do it a lot, but it's doable.

Alternately, you could create your own user function.

In this thread, starting at post 9, DaltonS gave me some code for creating my own functions, one of which was a tool to round to significant digits. (While I haven't finished work on the new sheet yet, I did incorporate most of his ideas in some form or another. The downside of this approach is that the sheet will claim you're using macros, and that seems to be something you were trying desperately to avoid, meaning you'll either have to use the formula in each cell or just live with Excel's limitation.

Re: [Space] System Generator
 

That's a niggle I come up against almost every time I do an spreadsheet work. It drives me nuts (or nuttier, perhaps).

Re: [Space] System Generator
 

I don't either, but it's what you get in spreadsheets, many monospaced fonts, and so on. Were I writing something up on a word processor, or by hand, for presentation I'd use proper superscript exponents. For forums and such I can't be bothered, 'cause I'm lazy.

I would, but I suspect some, maybe many, gamers won't know that 'normal' main sequence stars are dwarfs.

Fair enough.

Re: [Space] System Generator
 

And I think you (in advance) for it. I don't know how well Open Office deals with Excel macros these days, but in the past I was unable to use a number of spreadsheets that I found rather useful because they were written for Excel and used lots of macros.

Re: [Space] System Generator
 

Year length?

Re: [Space] System Generator
 

By about 6mm, IIRC.

Re: [Space] System Generator
 

I don't have my book with me, but if GURPS Space doesn't give rules for III vs. IV and II vs. I, then I agree--go with main sequence (or dwarf), giant, and supergiant.

They are and this should be done automatically as part of randomly generating a star system. Good luck with that. :) When I did it, I basically generated a complete system for the companion star(s), then got rid of any planets that were in the shared zone with a companion that had already generated planets for that shared region. I also list any companion stars as an orbiting body.

I prefer Greek letter for the star, Arabic numeral for the planet, lower case Arabic letter for the moon--ignoring moonlets.

Sol alpha 1
Sol alpha 2
Sol alpha 3
Sol alpha 3a
Sol alpha 4

If Sol had a companion star, those planets would read like

Sol beta 1
Sol beta 2

Obviously, you'd prefer to use actual Greek letters and not write them out.

Ah, that makes sense.

Are you saying non-water hydrograph coverage effects the Habitability Index?

Ah! I get it now. In that case, I can see why you'd want to include non-water hydrographics and not include a Resource Value.

Re: [Space] System Generator
 

But, isn't what you just said the RAW?

Then I'd go with: 'a', 'b', and 'c' for stellar companions, Roman numbers for planets, and letters for moons. It's a shame Greek letters are a hassle to implement. It's just too cool to be able to say "Ceti Alpha V". :)

Re: [Space] System Generator
 

Oh, that's right. The companions are typically small enough and/or far enough away that their effects are usually negligible on the primary star's planets. At least, that's what I tell my players. :) It may in fact be true in general.

I'm going to pretend I didn't read that.

Not according to Memory Alpha. Wow, Agemegos, this may mark the first time I've ever known you to be wrong.

Oh, that's right, they use Greek letters to ID stars in a constellation. So, forget Greek letters then. I say use capital letters to distinguish between companions, Roman numerals for planets, and lower case letters for moons. E.g. Alpha Centauri B IVe would be the 5th major moon around the 4th planet of the 2nd largest star in the Alpha Centauri trinary system. Now you've got to like that. (Wait, isn't that what you've been saying all along? It's late, I'm going to stop posting for the night.)

Re: [Space] System Generator
 

Me too ignant to follow completely. But blast it. I... want... all... your... systems'... results!
Though when going through numerous random rolling creations, I did come upon the most improbable sytem imaginable. Four earth type planets habitable to unprotected humans in a G2/G2/G2 star system, only one marginal atmosphere due to hazardous biologicals. Naturally, I named it "Bonanza".
Any idea just how unlikely my rolls were?

Re: [Space] System Generator
 

I prefer the 'IIIc' style - I think 'number, number' is more like to confuse when spoken than 'number, letter', and so IMO a hypothetical standards committee would favour this pattern (unless they're incompetent, of course).

As for sequencing, I say do all the moons - it saves kludgy namings when some insignificant rockball suddenly becomes a big deal down the road because someone puts a highly successful casino on it.

Re: [Space] System Generator
 

Or religious zealots.
Or simply places to crash. Close enough to see a garden world, but stranded on Podunk Dustball 3.

Re: [Space] System Generator
 

Admittedly I have little experience with proper astronomical designation rules. But using numerals for planets and letters for moons keeps them distinct and easier to read at a glance.
A simple number of moonlets with proper listing for major moons seems the best choice for gaming printouts. Especially since moonlets are often temporary things of which even large space stations might qualify.

Bonanza was a very strange set of rolls with no fudging on my part. One of the tow on the cold side of the habitable zones even had thicker than normal atmospheres rendering it even more comfortable for humans.

Re: [Space] System Generator
 

a) "obviously intelligent commentary" ? Hm. But you failed and didn´t deter me. :-)

b) All moons please. I don´t care whether letters or numerals.

c) Couldn´t the space for Hydrographics be shortened by using abbreviations like H²O or W and HC ? This would create space to show Mass and Density. IMO it´s interesting whether we find something with Density 3 or Density 7.

d) Would it be possible to say not just - for example - Thin atmosphere, but give the pressure as a number as well ? If necessary, I would even prefer the number.

Re: [Space] System Generator
 

Agegmegos, just so you know: I'm watching this with great interest. I'm sure it's an ungodly amount of work to type all those formulae into Excel.

As for the labeling: Why not simply use VI-l? Though the dot you used looks very stylish, too.

Re: [Space] System Generator
 

I don't think a whole line for each moonlet would be needed. Maybe devote one line to say how many of them there are, their inner-most and outer-most orbits, and that's about it.

Re: [Space] System Generator
 

I'm sure that is Agemegos's plan.

It looks like I'll get out-voted, but I would prefer not giving moonlets a number/letter. I'm sure gas giants have all kinds of crap orbiting them, from large planet sized moons to pebbles. At some point, you have to choose a cut-off and say, "Bodies smaller than--insert size here--will not be given a designation". Since moonlets aren't assigned a mass or RVM, they're not important enough to be given a number/letter, IMHO.

I am very pleased that Agemegos is considering using a letter designation for moons instead of a number. I recommend using upper case Roman numerals for the planet and lower case letters for the moons. E.g. VIIi. I wouldn't even bother with a bullet or period or a space to separate them. I agree, the "i" moons will be hard to read, but and the number "1" and the letters "I", "l", and "i" have always looked like each other and there's nothing to be done about it.

Re: [Space] System Generator
 

This looks great. Will the final version be available for download soon? Please??? :)

Mark

Re: [Space] System Generator
 

If I recall correctly, asteroid belts do get assigned an RVM. Assigning an RVM to the inner and outer moonlets would justify giving them a row in the survey. Assigning each moonlet an RVM would justify giving each moon a number designation. Personally, I just list the number of inner moonlets, ring type, and numer of outer moons on each planet's row.

Perhaps, Agemegos, you will usher that time in. Perhaps, that time is now! :)

Now that doesn't sound bad at all.

Re: [Space] System Generator
 

Looks pretty good to me. The only real color coding scheme that I think would be nice would be the orbital radius habitability zones. Otherwise, I don't think more colors would add much to it. If you do add one more narrow column, density would be a fine choice. That would give a general idea of the mineral wealth available. Not a huge thing, but meaningful in most of the space games I've played. Once again, fantastic work!

Re: [Space] System Generator
 

I'm surprised to see such long days on the first two gas giants, but maybe that's normal. I'm surprised to see superdence corrosive atmospheres on the gas giants. Is that GURPS RAW?

Since you've got day, year seems obvious; but I don't really think it adds much. You could add RVM; but this would imply these read-outs to be more than an "I look at the system. What do I see?" kind of survey.

I love colour! I'd limit it to very friendly stats in green and very alarming stats in red.

Joy!

Re: [Space] System Generator
 

I would still like "orbital period" (year for planets, month for moons) but perhaps that's just me. Otherwise it looks fine.

Re: [Space] System Generator
 

I don't bother generating atmosphere type for gas giants at all -- what's the point?

Re: [Space] System Generator
 

It does if the freakish rolls are freakish the other way. Or if you're the GM and you'd rather not have a total party kill at this point in the campaign. :(

Re: [Space] System Generator
 

a) I assume "infinite" solar day means "Tidelocked" ?
I would prefer Tidelocked then, as that´s the term used in the RAW (index) and the one I would google for.

b) Earth has HI 8. If earth is the gold standard, one could argue that HI 8 should get a seperate color. I don´t really see HI 3 as being habitable. HI 4 can be a breathable atmosphere but with no surface water and extreme climate, so I see HI 4 as the lowest interesting level. Which would mean HI 8, HI 6,7, HI 5,4, would each get a color.

c) The other color-coding would be chrome. Atmosphere, Hydrographics, Temperature are spelled out, and are short enough that a color doesn´t really save time reading. OTOH color might be used for other information: a red dot after world type could indicate high volcanism, a color code for Hydrographics could be used to indicate presence and complexity of native life for example.

d) Even if it would be an exemption: the world type row has enough space after "asteroid belt" to add the resource level. As that´s pretty much the only thing of interest in a belt, how about showing it ?

Re: [Space] System Generator
 

a) Space p.125 gives no change for Standard to Superdense. None is 0, Trace is less than 0.01. The only problem is the Thin to Very Thin change. Thin is 0.51-0.8, Very Thin is 0.01-0.5. How about simply subtracting 0.4 ? We don´t really know anyway, and I would much rather have a possible error of about 0.1 in this one special case than not to know whether I have 1.6 or 9 atms for example.

b) I would prefer both. I only mentioned the possibility to use the number instead of the category if some other change would make space that sparse. But right now the atmosphere row has enough space for both.

Re: [Space] System Generator
 

That leaves us with one color un-used - perhaps for HI 3 and below?

I find that color-coding not only makes a table easier to read, but also more pleasing for the eye (unless you use bright neon colors, obviously). I vote for using as much color coding as possible.

Re: [Space] System Generator
 

Oh ya, I remember having to deal with that. IIRC (my computer is not with me) I did something like generating random relative spacings, then converted the relative spacings into actual distances. Then, you can calculate tidal forces.

Who's to say the moons weren't closer a few billion years ago? I.e. The effect of random placement is much greater than the effect of tide locking increasing the orbit.

What? This sounds as if you didn't use the RAW to generate the planetary rotation parameters?

I've considered adding the actual atmospheric composition to all planets in general. E.g.
Generating random planetary atmospheres was something I wish was included in GURPS Space.

Re: [Space] System Generator
 

I'm intrigued by the "daily ±" for surface temperature. I'd be interested in a "seasonal ±" as well. How are you planning on determining these?

And I see you've only got one line for "main gases". It will be difficult to list the main gases and their % abundance in such a small space. Shall I assume this was a simple oversight and will be promptly corrected? :)

Getting back to how you calculate rotation period. You're using a corrected RAW, no? I know GURPS Space is in dire need of an errata update. But, you know what the errata should be, and you've applied it, and that is how you got your rotation periods, right?

Re: [Space] System Generator
 

Oxygen partial pressure or percentage would be nice, if it's available.

Re: [Space] System Generator
 

Oxygen partial pressure is an excellent idea in a human-centric universe. In fact, oxygen partial pressure in Earth partial pressure units would be perfect.

Re: [Space] System Generator
 

I think it's useful even without any humans in the universe at all. For one thing, if the intelligent species use oxygen it'll still be useful, and for another, the amount of oxygen available in the air has a major impact on the maximum size animals are likely to grow to, and on how big things like insects that rely on gas diffusion rather than lungs can grow.

Re: [Space] System Generator
 

You could use the shorter notations in the table, and then add a key as a footer or something. E.g. O2 = oxyger, N2 = nitrogen, etc.

The partial pressure of O2 is just: partial pressure of O2 = mole fraction of O2 * total pressure. So, the Maybe if/when you start determining the actually abundances you could add this feature.

The boiling temperature of water is a function of pressure. You could use a good water phase diagram to approximate what that function is.

and mass?

Bars is alright. Btw, what's the difference between the units bars and atmospheres?

Re: [Space] System Generator
 

I'm fine with bar.

Re: Day length, orbital period, annual period.
 

Apparent size would be really useful. So would the moon's significance in causing tides (unless that's linked directly to some other stat already available - I forget).

Re: [Space] System Generator
 

Of course, I was referring to using abbreviations on the system sheet, where the width of the columns is a premium and there are many rows. Alternatively, you could make a cover page with a key that you hand out once to new players.

True, but I'd rather see molar content/volume atmospheric abundances than tidal effects due to moons. I'm trying to convince you the extra work will be worth it (so that I won't have to bother with it :) )

Not much I guess. But, it's the most basic parameter a physical body has; as such, any self-respecting Planetary Record Sheet should include it. Unless--and this is perfectly reasonable--the intent of said sheet is *only* to provide info that readily impacts the space-farer's senses.

Apparent size would rock. That, and period, would allow you to easily describe them to player's on the planet's surface. Some moons orbit fast enough that you actually notice them moving across the sky. Some will appear to move backwards.

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That'd be cool. It's useful when considering how wide tidal zones are, how exciting any tidal bores might be, and how likely it is that coastal port cities dominate development.

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Good call on escape velocity. As for pressure, meh, who cares? Pick whichever unit you use the most. Conversion is as easy as typing, XXX Bar in kPa into google.

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That's why I wanted tidal effects. They are something character will notice, assuming they near a body of water big enough to have tides.

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For rough 'n' ready 1 bar = 100 kPa.

Re: [Space] System Generator
 

I'd prefer degrees.

If you include the orbital period of the planets on the system sheet, you could include the sidereal orbital period of the moons in the same column. On the planetary record sheet, you could record the apparent period of each moon. On the moon record sheet, you could record the solar orbital period of the moon, which the inhabitants would refer to as their day. Of course, I'm just throwing out suggestions. There could easily be better ways of providing this information; assuming it's worth providing in the first place.

Re: [Space] System Generator
 

Don't forget that tides vary away from the open oceans. The Bay of Fundy has the highest tides in the world averaging 52 feet versus the normal 3.

Re: [Space] System Generator
 

Incidentally, it's occured to me that tidal force should be derivable from the moon's apparent size and its density.

Re: [Space] System Generator
 

Will it be ready for download soon?

(Sorry...not trying to rush you...I'm just really looking forward to this.)

Mark