Topic: System generation

[Grimboldfrood]

I am looking at various planetary system generation rules. How much detail does SM go into in generating systems and worlds? Is it more or less than Traveller or D6, which are systems that I am familiar with?

Thanks

[markc]

There are no rules for system generation as I remember but it has been a long time since I have looked for any.
MDC

[arakish]

the original SM Gamemaster's book (whatever its actual title may be) has an abbreviated version.

if you are looking for more about the science behind system generation, you can take a look at what I written at my Stellar System Generation. 

Forewarning: I did update it this past June, but only to text the MathJax for the equations listed on the pages.  MathJax has worked for me at work, at college, and at home.  Let me know if it works for you or not.  Thanks.

I tried to give a layman's explanation into the basic science of system generation without going into too deep into the actual calculus and superphysics of stellar systems.

I will also admit that there is a lot of information at this site.  However, I did try and design it so anyone can generate as much information as desired or as little as desired.

rmfr

[dutch206]

AstroSynthesis from NBOS does a really good job of generating systems.  It's a computer program, so you don't even have to do any work.  Spacemaster suitability is high, as it doesn't get into details like races, etc.

[JimiSue]

Usually, I just make it up The vast majority of stars are main sequence (i.e. they are stable, and burning hydrogen or helium). If a system has native life of complexity, it needs rocky worlds in the biozone with stable orbit and relatively vertical totation, probably a decent sized moon, and one or two sizeable gas giants further out.

Large moons also a possibility, but don't have them too close to the primary or tidal forces from the gravity shear will make them so volcanic as to be unlivable. Also remember that each time they go around their primary they are going to have lengthy eclipses.

But in truth, we don't know a lot about solar system configuration other than our own solar system. Such exoplanets as have yet been found are on the large side, we're still trying to find anything very close to earth sized. The accepted view for some time was that when the sun turned into a star it blow all the remnant gasers out towards the edge of the system, which is why we have rocky worlds as far as Mars/asteroid belt and then gas planets further out. But the discovery of 'hot jupiters' has turned that on its head.

In short, most things are possible, so just make up a system how you like really

[providence13]

Don't know if they were scientifically accurate, but the Traveller: 2300AD rules were very thorough.
  I think that was different than Traveller.. (which later became MegaTraveller; I think.)

[Kristen Mork]

Also, check out the Stellar System Generation series from the Guild Companion, which starts here: http://www.guildcompanion.com/scrolls/2011/aug/ssg01.html

[Grimboldfrood]

Hi Guys

Thanks for the responses. Funnily enough, I saw SM 2ed GM book at DriveThruRPG.com for only $5 a few days ago so downloaded it to have a look at their generation system. I shall also have a detailed look at your suggestions for inspiration. I'll probably end up with some MacGyver'd version incorporating elements from all of them and then design an Excel spreadsheet to do the donkey work.

Many thanks

[arakish]

AstroSynthesis from NBOS does a really good job of generating systems.  It's a computer program, so you don't even have to do any work.  Spacemaster suitability is high, as it doesn't get into details like races, etc.

Only problem with AstroSynthesis is that the calculations made by the program are way off.  The closest I ever see any data get is +/- 25%.  I am currently in discussion with the NBOS AstroSynthesis team on helping them figure out why the calculations are so wrong.  One reason is they are using the wrong equations/formulas.  I am hoping they get it right soon.

However, AstroSynthesis does a very exceptional job on creating 3-D star maps.  I love it's ability to take your data and use it to generate maps of your universe.

Don't know if they were scientifically accurate, but the Traveller: 2300AD rules were very thorough.
  I think that was different than Traveller.. (which later became MegaTraveller; I think.)

I have never seen anything Traveller.  I know it was big in the early 80s, but I could never find it anywhere.  Then came Spacemaster in the mid-80s(??) and I never gave Traveller any further thought.

However, I have heard nothing bad about Traveller.

Also, check out the Stellar System Generation series from the Guild Companion, which starts here: http://www.guildcompanion.com/scrolls/2011/aug/ssg01.html

Thanks Peter.  That is the one I wrote.  My website, however, has been keeping that series updated.

The vast majority of stars are main sequence (i.e. they are stable, and burning hydrogen or helium).

Very true.  However, the vast majority (3 out of 4) of those class V (Main Sequence) stars are M Spectral stars and are not very well suited for life.  See this post: Star Spectral Classes for a listing of the number of class V stars.

rmfr

[JimiSue]

The vast majority of stars are main sequence (i.e. they are stable, and burning hydrogen or helium).

Very true.  However, the vast majority (3 out of 4) of those class V (Main Sequence) stars are M Spectral stars and are not very well suited for life.

OK - but if I'm designing a system, the primary will be the exact star type I want it to be!

[arakish]

The vast majority of stars are main sequence (i.e. they are stable, and burning hydrogen or helium).

Very true.  However, the vast majority (3 out of 4) of those class V (Main Sequence) stars are M Spectral stars and are not very well suited for life.

OK - but if I'm designing a system, the primary will be the exact star type I want it to be!

Exactly!  I just listed those numbers for GMs who want to use randomness, or want a sense of what actually exists out there as far as we know.  I will always say, and do so several times in the Stellar System Generator I wrote,

"Do not enslave yourself to the dice!  You can always simply choose what you want."

rmfr

[Grimboldfrood]

As I thought, I ended up with a spreadsheet that does the donkey work. It's a mixture of SM 2nd ed GM and Traveller generation rules, so it was great fun sorting out how to make the two systems relate to each other. It does have its limitations, however. For instance, I don't like having gas giants or asteroid belts being capable of supporting a civilzation, so if I have more habitable worlds in the system than available planets, the remainder are lost.

[dutch206]

re:  SM2 GM Guide.  Please keep in mind that this was written quite some time ago.  Astronomy has learned SO much more since the launch of the Hubble Space Telescope.  (In particular:  Stellar classes N and S are no longer used, there is a new category called "dwarf planet", and Jupiter and Saturn have more moons/rings than anybody ever suspected.)

[markc]

re:  SM2 GM Guide.  Please keep in mind that this was written quite some time ago.  Astronomy has learned SO much more since the launch of the Hubble Space Telescope.  (In particular:  Stellar classes N and S are no longer used, there is a new category called "dwarf planet", and Jupiter and Saturn have more moons/rings than anybody ever suspected.)

No way! We have learned something new in the sciences since the 80's. I do not believe it.
 
MDC

[JimiSue]

As I thought, I ended up with a spreadsheet that does the donkey work. It's a mixture of SM 2nd ed GM and Traveller generation rules, so it was great fun sorting out how to make the two systems relate to each other. It does have its limitations, however. For instance, I don't like having gas giants or asteroid belts being capable of supporting a civilzation, so if I have more habitable worlds in the system than available planets, the remainder are lost.

What about moons of gas giants? Many scientists are quite upbeat about the possibility of finding life on Europa for example. If the gas giant is closer into the sun so the temperature becomes more habitable, then it could be possible to have life on a solid surface as well. We know there are 'hot Jupiters' out there - there's no reason why one couldn't therefore also form in the habitable zone around a sun.

Also bear in mind that a civilisation might not be native to the system - a degenerate remnant of what are known in SM2 as Sianetic harbingers. You might for example have a whale-like species that swims in the atmosphere of a gas giant, feeding on the hydrocarbons to be found there. Even an asteroid belt could support a community of miners from a distant civilisation who have been cut off from home for centuries, who have survived by hollowing out one of the larger asteroids, perfecting their Oxygen reclamation, and extracting oxygen from the asteroids around them to replenish any that they lose.

Don't let tables over-rule imagination! Tables are useful when imagination fails, but your brain should always be your first port of call.

[Grimboldfrood]

Don't let tables over-rule imagination! Tables are useful when imagination fails, but your brain should always be your first port of call.

Yes, I agree. That's why I have ignored the tables in SP2 GM that allows civilizations on gas giants and asteroids. Doesn't stop me adding one of course, as I can just over-write the Excel results. However, for the purposes of generating a system, populating it, calulating law and technology levels, trade etc, my spreadsheet does me fine. If I don't like the results, I just hit F9 and get a new result. 

It's also quite easy to update when new information about the cosmos becomes available, or if I see a better system. For instance, last night I found Cosmos2 so have downloaded it and will compare it to my spreadsheet to see if it produces systems more suited to my campaign. If it does, I can just change those aspects I like and leave the rest. However, at the moment, I am looking at SSG for inspiration and possible tweaks.

[markc]

Don't let tables over-rule imagination! Tables are useful when imagination fails, but your brain should always be your first port of call.

Yes, I agree. That's why I have ignored the tables in SP2 GM that allows civilizations on gas giants and asteroids. Doesn't stop me adding one of course, as I can just over-write the Excel results. However, for the purposes of generating a system, populating it, calulating law and technology levels, trade etc, my spreadsheet does me fine. If I don't like the results, I just hit F9 and get a new result. 

It's also quite easy to update when new information about the cosmos becomes available, or if I see a better system. For instance, last night I found Cosmos2 so have downloaded it and will compare it to my spreadsheet to see if it produces systems more suited to my campaign. If it does, I can just change those aspects I like and leave the rest. However, at the moment, I am looking at SSG for inspiration and possible tweaks.

 You have hit upon one of the magic quotes of RPG's "...if it suits my campaign." Or as I like to call them Rule 0's.
MDC

[Grimboldfrood]

Or as I like to call them Rule 0's

Oh, you mean the first commandment of roleplaying...

"I am the Lord thy DM. Thou shalt have no other DMs before me.   

[arakish]

@Grimboldfrood

In my current SM campaign, there is a species who live on gas giants similar to Jupiter.  And they go from system to system through some means that is unknown to the others.  This species, named the Hoobar, generally ignore all the others.  And the others have no way of enforcing their desires upon the Hoobar.

"I am the Lord thy DM. Thou shalt have no other DMs before me.   

Actually in my rules they go:

Rule 0: A GM has the right to change any rule in a book to fit their game.
Rule 1: I am your Lord thy GM.  Thou shalt have no other GMs before me.
Rule 2: All complaints are to be taken to the GM's wife.
Rule 3: If ever in doubt, refer to Rule 1.
 

Don't let tables over-rule imagination! Tables are useful when imagination fails, but your brain should always be your first port of call.

My sentiments exactly.  I only use a SSG when I need to make a new system real quick and on the fly.  Usually, I only focus on the star, number of orbits, and the planet within the Biosphere Radii.  Otherwise, I make up the rest as needed.  But I still do use my SSG as a guideline because I always want to make a system feasible, even though it is imaginary.

rmfr

[Grimboldfrood]

Read through Cosmos 2 today. Seems a quick flexible system, so worth looking at for tweaks. A bit unclear about the GRAPH references, however. I have no idea what the real-world equivalents are for Radiation, Pressure or Heat. I found Gravity, i.e. G0<0.2 earth gravity, and G1 is between 0.2 and 0.8 earth gravity etc but the others are a mystery. I feel a fudge coming on!

Interesting how other people design star systems. For myself, I generate the whole system and the results give me ideas for the background. So, large planet, insidious atmosphere, interstellar technology level, but only a few hundred population. Sounds like it could be a mining complex or possibly a terra-forming project - LV426 anybody? 

"Nuke it from orbit - it's the only way to be sure!